When Rudi Skacel asked to have the number 51 printed on the back of his Dundee United shirt he likely thought it was no big deal; an homage to the 5-1 Scottish Cup win with Hearts last season but one subtle enough that nobody was going to pick up on it.

One public apology from his new manager later and the Czech is still a little bemused by it all.

Peter Houston claimed he had not known the significance of the number when he signed Skacel last week, and apologised for any offence caused to Hibernian fans – whose side were vanquished by their Edinburgh rivals in that final – after giving the forward his United debut in the win over St Mirren.

There will not be any need for contrition tomorrow night. United go to Tynecastle for a Scottish Communities League Cup quarter-final tie with Hearts and Skacel could turn out against his former side. His squad number as well as fond memories of his scoring exploits – Skacel scored 18 goals for Hearts last season – will afford him a warm welcome but the forward will be careful not to allow such sentiment to affect his performance.

"I am glad the United supporters are okay with [him wearing No.51]. It is only a number and I think it is stupid, all the things about this," said Skacel.

"I don't care about Hibs. I care about United and will make sure I do everything for the club – that's it."

"For me this is another game but it is also a little bit special. It will be a little bit weird to play against Hearts but I want to make sure I do everything for Dundee United and we go [through] to the next round. It is in the past – my time at Hearts. I don't speak about that. I am focused on United and will try my best for them. I want to get through in the cup and that's it. Hearts will be my enemies for 90 minutes."

United will be his friends for three months. Skacel arrived at Tannadice having agreed a short-term deal having spent recent weeks training at Riccarton. The deal may be extended in January should Skacel rediscover the sort of form that made him a cult hero at Hearts, but for now he will settle for helping United into the last four of the League Cup.

"I want to do my best for my team – I want to score, want to win and want to go for another round," said the Czech. "I have come to United to help them win games. I don't want to lose.

"So even this game they are for 90 minutes my enemies. I have good memories of my former club but now I have to make sure I do everything for my new team.

"Every game is important. I am a bad loser and don't want to lose any match – no matter what tournament it is in. Wins build confidence and, hopefully, the St Mirren game will help us to go on a good run. We will see if I start. I have been training and gaining fitness all the time.

"I felt great after Saturday but that was because we won the game. It is always easier than when you lose."

While Hearts fans will relish the return of Skacel – at least until kick-off – United supporters may also be given a fleeting glance of a player they have come to hold in equally high regard.

Gary Mackay-Steven has been out of action since undergoing a knee operation last month but will return to the squad to face Hearts.

"Gary is back in the squad. He's been training hard recently so is back in contention," said Houston. "He's nowhere near ready to start but it's a possibility he may be on the bench."

Houston, meanwhile, has said the win against St Mirren was down to changing to an elementary approach.

"We've picked up in the last two games," the United manager said. "It was a solid performance and since we've tinkered it and gone back to basics it's worked well."