Mackail-Smith believes Peterborough tie has come at an ideal time

The 31-year-old heads back to the ABAX Stadium with his Hatters’ team suffering back-to-back defeats in the league, conceding seven goals in total against Carlisle and Newport County.

It’s the exact opposite for Posh, who have won five in a row, putting four past Scunthorpe last time out.

But Mackail-Smith said: “I think Peterborough is a good game to go into at this period where we’ve come off the back of two poor results.

“Playing against a team in a higher division will show we can play with the big boys and hopefully that will give us confidence going into the league.

“They have been scoring all those goals and now they’ll come into a cup game and maybe they might relax a bit.

“It might just give us that little edge to get in there, hopefully score the first goal and put a decent performance in to give ourselves that boost going into the rest of the season in the league.

“The league hasn’t quite gone how we wanted it to, the last two games haven’t panned out. But it gives us that break to go and play against a good team in good form to show as a team we can cope at the next level and we need to perform week in week out at this level to show we can do that.”

Mackail-Smith is something of a club hero at Peterborough, winning a number of promotions in his time with them, scoring 99 goals too.

With Posh now enjoying a resurgence under new boss Graham Westley, the striker admitted it has a similar feel to when he was there, although he wants to do a professional job for his new side.

He continued: “I’ve kept an eye on results, they did struggle a bit at the start of the season, but the last few games they’ve scored 13/14 goals, so it’s definitely how it used to be at Peterborough.

“On Sunday though I’ll go there as a Luton Town player to score goals and put us through to the next round of the cup.”

With Mackail-Smith having featured for Scotland and at Championship level, while the likes of Paddy McCourt, Nathan Doyle and Scott Griffiths, to name a few, all playing at a higher level, Mackail-Smith doesn’t believe the game will have any fears for his side.

He added: “We’ve got players on the pitch that can cause them problems, we showed that against Stoke and showed that against Bristol City.

“We know what we are capable of, it’s just putting that in a run and keeping that run consistent.

“We’ve been up and down, had a couple of results and then lost a couple, but it’s a one-off game, it doesn’t matter what kind of division they’re in.

“For us we want to win and take some form into the Northampton game, as I think a good performance will help us build stepping stones to the next game.”