BILLY MEHMET did not score a lot of goals during five years as a St Mirren player but plenty were loaded with significance.

His first took a while to arrive – he had the misfortune to fall ill with mumps not long after arriving from Dunfermline Athletic – but it ended up being the goal that clinched the first division title. Twelve months later, he ended a seven-month goal drought by scoring in a come-from-behind victory on the penultimate day of the season that kept the club in the top division.

Two years further on and it was his penalty that helped St Mirren beat Celtic for the first time in 19 years, while the next season he was making history again, his strike propelling the Paisley club into a first League Cup final in 55 years. "Even just thinking about it all now sends shivers down my spine," Mehmet tells Herald Sport from his home in Thailand. "St Mirren was a massive part of my life and that's where I was happiest in my career. We had some fantastic times there."

There was a surprise element attached to many of Mehmet's important goals as they tended to arrive when all hope was seemingly lost. It is a story that may imbue St Mirren players, staff and supporters with confidence ahead of tomorrow's Scottish Communities League Cup tie against Celtic. It is the first time the Paisley club have reached the semi-finals since Mehmet intervened to see off Hearts three years ago. Jim Jefferies' return as manager just a few days earlier meant the Tynecastle side were strong favourites to progress but, on a rutted Fir Park pitch, it was Mehmet and St Mirren who prevailed.

"It was such a big moment for me," he said. "Hearts had gone into the game as favourites and we were given little chance but we put on a great performance. To cap it off with a goal in front of the St Mirren fans was one of the best feelings I've ever had in football."

St Mirren have been given little chance of causing an upset tomorrow against a Celtic side enjoying a rich vein of form. Mehmet, however, knows from personal experience that things don't always turn out as expected. The Londoner was part of a St Mirren team that went to Celtic Park in February 2009 and lost 7-0 only to rebound in spectacular fashion just seven days later by knocking the same opposition out of the Scottish Cup.

"That was a massive game for us," Mehmet recalled. "I was waiting to take the penalty, trying to keep calm and, when I saw [Artur] Boruc dive the wrong way, it was a great feeling. A week before we had lost 7-0 and we were determined to show we weren't as bad a team as that result suggested. To beat Celtic the following week, in front of our own fans, showed the character we had as a group."

That character would be tested to its limit a year later when St Mirren lost in the League Cup final to a Rangers team reduced to nine men. They would demonstrate significant resolve just three days later by beating Celtic 4-0. "In the final, we had great opportunities; shots cleared off the line and all sorts. It was all in our favour. I think we got excited and saw the opportunity opening up to win the trophy. Then we got caught by a sucker punch, they had one chance and Kenny Miller put it away. That was so disappointing and we really hurt. But we had Celtic just a few days later and knew we had to put it behind us. And we bounced back in real style, smashing them 4-0. That was an unbelievable night."

It gives Mehmet hope that his old team can cause an upset tomorrow. "I'll be watching it and hoping St Mirren can do it. And they've got a real chance. It's going to be difficult but they just have to try to nick a goal and hold on. I just hope they go one better than we did and go on and win the whole thing."

Mehmet has embarked on something of a wandering career since leaving Scotland in 2010, playing first in Turkey, then Australia before arriving in Thailand a few weeks ago after agreeing a two-year deal with Bangkok Glass. Still only 29, the striker has not ruled out one day returning to Paisley.

"I do miss Scotland and a lot of St Mirren fans send me messages on Twitter asking me to come back and I would love that one day. I've spoken to my agent, family and Steven McGarry [a former team-mate at Perth Glory] about it and we'd both love to go back to St Mirren. It's one of those clubs that your heart grows with. That happened to me. I would love to finish my career there."