The Buddies are on a high after last week's shock 3-2 Scottish Communities League Cup semi-final win over Celtic at Hampden, which they followed up with a 2-1 Clydesdale Bank Premier League win over second-placed Inverness in midweek.
Lomas' side, for their part were "buoyed" by their 3-1 home win over Aberdeen on Wednesday which leads the Northern Irishman to think the fans could be in for a treat.
The Saints boss said: "St Mirren have done brilliantly and they were doing well before Christmas so I'm sure Danny (Lennon) didn't want the winter break to come.
"When they have everyone fit, they are a good team. They have good players like Stevie Thompson, Paul McGowan and Gary Teale, who has Premier League experience, and they have good young players like Kenny McLean, so they have a good mix in the team and it is going to be a tough game all right.
"But our performance against Aberdeen was good, although I thought we also played well against Motherwell in the previous game to that even though we lost.
"But we were delighted with the result against Aberdeen and I get the feeling that this is going to be an old-fashioned cup tie with two teams who like to attack so there could be plenty of goals."
Lomas was pleased with the way the Perth club came out of the transfer window after he signed Newcastle's Mehdi Abeid, 20, and Swansea's Gwion Edwards, 19, on loan until the end of the season.
They join 20-year-old QPR midfielder Michael Doughty, who made his debut against Aberdeen after also joining on a loan deal as midfielder Kevin Moon left the club by mutual consent.
Lomas said: "We are lucky to have been helped by three Premier League clubs. We have trimmed the seniors down and added a few under-21 players. It is a good opportunity for them. The SPL is a good level of competition to test them and it will take them away from any comfort zone."
- Sports & Recreation
- Clydesdale Bank Premier League
- Premier League