Saints stayed clear at the top of the Super League and got a morale boost for their next meeting with Bradford at Wembley, but the Bulls had more than enough opportunities to win this pulsating game in the second half.
A hat-trick of tries from Matt Calland, playing against his local club, was not quite sufficient to retrieve the spoils for Bradford, but if a string of other chances had been taken, Saints' unbeaten record would be a thing of the past.
Bradford trailed 24-8 at half-time after being swept aside by a home team continuing its commanding early season form. But they showed remarkable character to lift themselves after the break and take the initiative.
Calland, running with power and purpose in the centre, profited from the handling of Graeme Bradley and Paul Loughlin to go in for a try and if Paul Cook had not missed his conversion for the third time, Bradford would have made deeper inroads into Saints' lead.
The decisive factor, though, was that series of chances that were carved out without being accepted. A pass from Bradley went astray with the left flank open, Brian McDermott lost the ball going for the line and the outstanding James Lowes put the one blemish on his game by losing control as he went over.
Jon Scales was pulled back for an earlier offence and glorious play from Robbie Paul was only denied the try it deserved by a great cover tackle from Danny Arnold.
Bradford did finally get over the line, Calland claiming his third try and Steve McNamara adding a conversion and a penalty to bring them within four points.
The penalty also saw Saints reduced to 12 men with Vila Mitautia sent off for using an elbow on Simon Knox, but Bradford's last opportunity came and went when Carlos Hassan kicked ahead too firmly. When McNamara was sent to the sin bin for holding down, Bobbie Goulding's fifth goal saw Saints home.
Such a tight finish had seemed inconceivable in the first half when tries from Arnold, Scott Gibbs and a 60-yard scorcher from Apollo Perelini had put Saints well in control.
"It was the worst performance since I came here," said their coach, Shaun McRae, of their second half decline.
Brian Smith firmly believed that his Bulls deserved to win and might have done so if they had been allowed an extra substitute, to which he claimed they were entitled, when Knox was carried off.
He has the extra worry before Wembley that Sonny Nickle was placed on report for appearing to kick out in the tackle. Both he and Mitautia will learn their fates this week.
St Helens: Hunte; Arnold, Gibbs, Newlove, Sullivan; Hammond, Goulding; Perelini, Cunningham, Leathem, Joynt, McVey, Morley. Substitutes used: Martyn, Matautia, Pickavance. Substitute not used: Hayes.
Bradford Bulls: Cook; Christie, Calland, Loughlin, Scales; Bradley, Paul; McDermott, Lowes, Ireland, Nickle, Dwyer, McNamara. Substitutes used: Donohue, Hassan, Medley, Knox.
Referee: R Smith (Castleford)Reuse content