The Perth men are one of two sides to have beaten Celtic in the SPL this season, having won at home in September. Kilmarnock's win last month came days after Celtic lost in the Champions League to a last-gasp winner in Barcelona, but this weekend's fixture comes after Wednesday's memorable victory for the Hoops. Lomas, who watched the match on television, said:
"They did very well. I thought tactically and how they went about it was top notch.
"Barcelona had the majority of possession, but they worked very hard, as a group stayed very compact and conceded the wide areas because they know Barcelona don't cross too many (balls).
"It was a great atmosphere as well. Celtic Park was bouncing."
The comparison may be crude, but Celtic could be performing the Barcelona role, with Saints performing the role of the underdog, this weekend. Lomas added:
"Nine times out of 10 you go to Celtic Park they have the lion's share of possession, but there's many ways to skin a cat."
Lomas takes confidence from his side's 2-1 win at McDiarmid Park on September 15 and the victory in the east end of Glasgow last season. He added:
"We've had some of the better results. We won away there last year under Derek (McInnes, Lomas' predecessor), we won at home earlier in the season.
"We know the size of the task. It's a tough task. Celtic probably need to be under par, we need to be at our best.
"We're only focusing on ourselves. We can't do anything about Celtic, about the tactics, about how they play, whether there's a Barcelona hangover.
"All we can do is try to do what we're good at."
The home win over Celtic sparked a run of six victories in all competitions before a draw with Inverness and a 5-0 defeat in the Scottish Communities League Cup quarter-final at Parkhead. Saints, who lost their last SPL outing to Motherwell, will be eager to prove that was a one-off and not a true reflection of their capabilities.
"We've got to play better, it's as simple as that," Lomas added.
"You don't go to Celtic Park and get anything if you play poorly.
"It's a good opportunity to bounce back after the cup game and put in a better performance and we'll see where that takes us."
Saints' resources have been stretched in recent weeks, but defender Callum Davidson (back), midfielder Paddy Cregg and winger Peter Pawlett (both hamstring) are nearing returns, with Craig Beattie (thigh) and Jamie Adams (back) likely to still be absent.
"The last five weeks or so we've been very close to the wind in terms of squad numbers, so it certainly will help," Lomas added.