Fa'asavalu came off the bench for St Helens to devastating effect
St Helens recovered from a 14-4 first-half deficit to beat Bradford for a record-breaking 16th consecutive away Super League victory.
Glenn Morrison and Rikki Sheriffe tries gave Bradford early hope.
But Saints regrouped and James Roby, Jon Wilkin, Chris Flannery and Kyle Eastmond crossed in the space of 13 minutes to put them in control.
Bradford threatened a revival through Semi Tadulala but Saints ran in three late scores to seal the win.
The visitors, without Sean Long because of a thumb injury, opened the scoring through Francis Meli in the left corner but they were below their best and Morrison and Sheriffe capitalised.
The introduction of forwards Maurie Fa'asavalu and Tony Puletua combined with improced discipline helped Saints - and when Roby scored on 27 minutes under the posts after bundling over from dummy-half, it started the fightback.
Wilkin got onto the end of Flannery's grubber kick before Flannery himself crossed and Eastmond added to Bradford's misery just on half-time from Puletua's offload.
Both sides struggled to challenge the line at the start of the second half but Bradford gave themselves some hope when Tadulala took Chris Nero's offload, although Deacon failed to convert.
Scores from Fa'asavalu, Puletua and Meli, with his second try of the afternoon, put the game beyond the struggling Bulls, while Eastmond finished with six goals from eight attempts as Saints moved four points clear at the top of the table.
Bradford coach Steve McNamara:
"Saints had two red-hot spells, one in the first half and one towards the end of the game, but apart from that I thought it was a very even contest.
"We were in control for a large part of that first half and were very, very enthusiastic. For 25 minutes we were sharp offensively, defensively and controlled the game.
"But the arrival of Fa'asavalu, Puletua and Roby really seemed to be the catalyst for them. And they did what has made them the best side in the competition; they punished us for making mistakes. This is a harsh, cruel game and we need to learn lessons from it."
St Helens coach Mick Potter:
"We decided to change it around in the first half and it certainly paid off. Robes (James Roby) showed how quick he is out of dummy half and can add some real value to our team off the bench.
"Maurie (Fa'asavalu) was also very good today. He was dynamic and you wouldn't want him running at you, let me tell you. I think he enjoyed his try there at the end and it was well taken.
"It was a very physical game and that's the way Bradford play. It was hard for us."
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