Lomax, who made his Saints debut as a full-back in 2009, was switched from his customary scrum-half role to plug the gap caused by injury to skipper Paul Wellens.
"He certainly played well," said Brown of 22-year-old Lomax. "The best modern-day full-backs are half-backs. He's athletic, he can pass and kick and see the game well. I don't think it was a genius move."
Lomax set the scoreboard ticking over with his first try after only two minutes and Saints had the game won at half-time when they led 26-0.
Willie Manu scored his first try for the club and Tony Puletua, Ade Gardner and Anthony Laffranchi also touched down as Saints produced their best display of the season, to set themselves up nicely for next Friday's clash with Leeds, who are fresh from their World Club Challenge defeat by Melbourne Storm.
"We're improving," said Brown. "From round one to four, we have definitely got better. I thought in the first 40 minutes we played with good discipline and control. We let ourselves down in the second half but we did things more consistently for longer.
"I'm sure we'll improve again. It will be a big challenge next Friday. Leeds are a good side and they did the competition a good service with the way they performed."
Bradford never fully recovered from their woeful start but salvaged some respect with second-half tries through Brett Kearney and Elliot Kear.
"We had very little possession in the first half an hour," said Bulls coach Francis Cummins. "They got a good roll-on and we spent too much time near our own goal-line.
"You can't afford to play against the main teams without the ball. At the back end of the first half we asked some questions. We opened them up but couldn't finish off. I was pleased with the fightback and in the second half we were able to trade sets but we need more quality than that to beat St Helens."