
The randy goalie - who's engaged to blonde Leah Shevlin - was driven potty by the reality show star at a glitzy party.
He smooched with her and let his hands wander all over her shapely backside.
And in a desperate bid to line up a shot with sultry Saffia, McGregor tried all his best lines in a frantic text-message bombardment.
But he snookered himself after lying about his fiancée - claiming all his relationships and womanising ways were in the past.
And last night brunette bombshell Saffia told us how the Ibrox playboy:
FLIRTED with her and told her she was stunning just minutes after they met
GROPED her on the dancefloor before tailing her to the toilets
SNOGGED her in front of the packed party before groping her bum
BEGGED her repeatedly to go back to his hotel room with him, and
BOMBARDED her with a string of texts, begging for photos and a meeting where "anything would be on offer".
But the BB beauty showed the keeper the red card as soon as she realised he'd had no big break from fiancée Leah, 26.
Saffia said: "It didn't take long before I realised what he was all about. I didn't trust him from the start - he was only after one thing and there was NO way I was giving it.
"We'd only just kissed and he was harassing me to go back to his hotel room with him. He clearly thought I was going to be easy, like most of the silly little girls he is used to.
"I hadn't a clue who he was and really wasn't that impressed. But the fact I stood up to him made him even more keen.
"But as soon as I heard he had a girlfriend, I made it very clear that I wasn't interested.
"He tried to make out that all the girls linked to him were in the past but I knew that wasn't true and cut off contact.
"I feel really sorry for his girlfriend - her man is out looking for sex with other women behind her back. I'm just glad I kept my self respect and walked away when I realised he was attached. In fact, that probably makes me one of the first girls from Big Brother to actually turn down sex with a celebrity after the show."
McGregor, 27, met sexy Saffia at a glitzy party at London's O2 arena to mark the end of this year's Big Brother.
Housemates past and present turned out for the bash, including the Gers shot-stopper's pals Kenneth Tong, 24, and Karly Ashworth, 21 - both stars of this year's Channel 4 show.

And they introduced the footballer to pretty Saffia who sensationally quit BB10 after just nine days. Last night she told how McGregor - who wasn't wearing an engagement ring - started flirting right away.
Saffia said: "I had absolutely no idea who he was. In fact, I thought he was a snooker player because he was wearing this weird waistcoat and a silk shirt.
"When I told him that, he seemed to think it was really funny. I think he is used to girls being impressed by who he is. From the minute we met, he was all over me. I had a pretty little black dress on and he kept telling me I looked absolutely stunning.
"He was standing very close to me, leaning in towards me, touching my arms and back."
Saffia, a beauty consultant from Nottingham, continued: "I thought he was all-right looking and we got on well at first. We had a good laugh with each other.
"He has a very thick Scottish accent and I was struggling to understand him, so I joked he needed subtitles. He definitely liked the fact I was able to hold my own and make fun of him. I get the impression most women aren't much of a challenge for him."
The gagging-for-it goalie followed Saffia on to the dancefloor, where he tried to get close. The English stunner explained: "I went for a dance with my friends and the next thing I knew Allan was there behind me.
"He wasn't a very good dancer and he kept trying to get up close to me, trying to grab my back and arms. His hands would have been everywhere if I'd let him."
Even when Saffia headed for the TOILET, determined McGregor tailed her there.
The single mum-of-two said: "Every time I turned round, there he was again. When I went to the loo, he came along, telling me he knew the way. He then waited outside for me and when I came out, leaned in for a kiss.
"At that point, I just knew him as Allan - a single Scottish guy who seemed nice enough. I was quite attracted to him at first. We got on and I saw no harm in having a kiss.
"He was actually a really good kisser - but straight away his hands were moving over my body and he grabbed my bum.
"The kiss lasted for a good few minutes, in full view of everyone at the party. From his behaviour, I had no reason to think he was attached - he wasn't exactly trying to hide what we were doing."
But Saffia was turned off by McGregor's desperate bid to get her back to his room. She said: "As soon as we kissed, he started asking me if I'd go back to his hotel.
"He wouldn't take no for an answer and kept hounding me about it, which annoyed me - he assumed I was that easy.
"I was really put off him after that and went back to dance with my pals. I left the party not long after that. I just got up and went without saying goodbye to him."
But persistent McGregor was hooked by then and begged pals for her number. Saffia was stunned when the next day the player sent a picture message.

She told us: "I was a bit freaked out. I had no idea how he got my number, but I found out later it was through a friend.
"My pal then told me who he was but it didn't make any difference to me. Allan sent me a very random picture of himself on what looks like a train home.
"I wasn't sure what the point in that was - but I was suspicious he would start asking me to send pics."
A few texts later, McGregor proved her right. In a text sent at 12.14pm on September 6, the day after the Big Brother party, he gushed: "How's your day gorgeous x."
Saffia joked he probably wouldn't remember who she was - but McGregor replied: "Come on babe, I would never forget. x."
He then asked the pretty former make-up artist to visit him in Glasgow. The keeper texted: "I feel like s**t, when are you coming to visit me? x."
Saffia said she had to do a radio interview in Dundee and McGregor saw his chance.
He replied: "It's s**t, come down to Glasgow after it." He added: "Bring your snooker cue ha ha, your more than welcome anytime.
"Bring your chalk too so that you can chalk my cue x."
McGregor then asked Saffia for PICTURES. In a text sent at 12.22pm on the same day, he wrote: "You got any photos for me x?"
Shocked Saffia refused to send pics and suggested they become friends on Facebook instead. But a rattled McGregor replied: "No babe, TOO DANGEROUS x."
That reply rang alarm bells for Saffia, who started to worry the Gers star had a girlfriend - and a quick Google search proved her right.
She told us: "I was just so suspicious of him, I've met his type before and they really are all the same. I looked him up online and there were all these stories about girls he'd been with and that he had a fiancée.
"That was the final straw for me. I am just not interested in a guy like that."
Saffia decided to break contact with McGregor but the smitten star sent texts over the next week - asking for a meeting and pursuing her relentlessly.
And when she called his bluff over his relationship, the lying love rat DENIED that he was attached. In a text sent on September 13, he said: "All the s**t has happened in the past. Anything you like is on offer, from yours truley x."
He added: "I wouldn't say I was a player, I just thought when we met each other that night we got on well x."
Seething Saffia sent McGregor packing - but he still left his offer open, saying in a text: "Well if your up here give me a shout x."
Last night Saffia told us she reckons she's had a lucky escape. She said: "I am so glad I had nothing to do with that guy. I kissed him when I thought he was single but that was it. I have done nothing wrong but he knew exactly what he was doing and would have slept with me if I'd allowed him.
"I am no pushover and I think that actually made him chase me even more. But I want other girls out there, including his fiancée, to realise exactly what this guy is like and avoid him like the plague.
"It's really not right that these guys get away with treating women like s**t because of what they do.
"It's time he was shown up for the shameful CHEAT he is."

McGregor was pictured with BB pals Karly and Kenneth in London's famous Cock Tavern the day after the O2 bash. Karly posted snaps of him playing pool on the internet.
The glamour model, from Methilhill, Fife, hit it off with Saffia after they both entered the Big Brother house in June.
Saffia walked off after nine days because she was missing her two kids, then Karly became the seventh housemate to be evicted. Days later, Kenneth escaped the BB house.
The latest revelations about McGregor come after we told in May how he booked into a Glasgow city centre hotel with stunning model Sarah Bennett, 21, after a night out at a nearby club.
They were spotted collecting a key and going into a lift before McGregor left 45 minutes later.
In August, McGregor's fiancée Leah defended her man over the incident, claiming he'd been TOO DRUNK to cheat.
Part-time model Shevlin started dating the £25,000-a-week keeper last February after he bought a Bentley from the Hamilton garage where she worked.
McGregor moved the blonde into his Glasgow penthouse flat two months later. And in April last year, he popped the question on a luxury holiday in Dubai.
But three months later, claims surfaced that the keeper had sent romantic texts to old flame Bronwyn Campbell, 29, just hours after his proposal to Leah.
And the pair allegedly met for secret dates in October - behind her back. Shamed McGregor, who signed for Rangers in 1998, and former Ibrox team-mate Barry Ferguson, 31, were both banned for life from playing for Scotland after the Boozegate scandal earlier this year.
The pair had a wild drinking binge at the team's Loch Lomondside hotel Cameron House in March - then made V-signs while sitting on the substitutes' bench days later.
Last night McGregor - who played in Rangers' 2-1 victory over St Johnstone yesterday - was unavailable for comment.