The Black and Whites fought back from 22-12 down to draw level with the aid of Richard Whiting's 72nd-minute try and ought to have taken both points after dominating the final quarter.
But Holdsworth, who had helped create all four of his side's tries and kicked three superb conversions, missed a kick to win it and was also wide with two long-range drop-goal attempts in a frantic finish. That left St Helens relieved to salvage a point after once more looking distinctly out of sorts, despite the return from injury of influential hooker James Roby.
The Black and Whites were aiming for a third win in four visits to St Helens and they made a dream start, with right winger Jason Crookes taking Holdsworth's pass to score the game's first try after only four minutes.
Crookes undid much of his good work by dropping the ball from Lee Gaskell's high kick that led to Saints' equalising try and went off injured almost straight away. Slow-starting Saints actually took control of the match with the aid of a three-try burst inside 17 minutes.
Prop Anthony Laffranchi took Roby's inside pass to cross, skipper Paul Wellens combined with Josh Jones to get winger Francis Meli over for his third try of the season and former Hull centre Jordan Turner stepped inside his old team-mate Kirk Yeaman to open his account for the club.
Gaskell kicked two of his three conversions as St Helens led 16-6 but the introduction of hooker Aaron Heremaia injected new purpose into the visitors and they cut the deficit nine minutes before half-time when impressive full-back Shannon McDonnell won the race to Holdsworth's perfectly-judged kick to the line. Holdsworth's second goal made it 16-12.
Saints extended their lead when centre Jones crossed out wide for their fourth try on 49 minutes but Hull once more kept in touch when England winger Tom Briscoe profited from Holdsworth's pinpoint kick to the corner to claim his side's third try.
Holdsworth's immaculate touchline conversion again cut the gap to just four points and the visitors thought they had equalised on 63 minutes when Briscoe crossed again, only to have the try disallowed for a forward pass.
Hull's pressure finally told on 71 minutes when Holdsworth and Richard Horne combined to get centre Whiting slicing through for Hull's fourth try. That levelled the scores but Holdsworth was off target for the first time and he was also wide with two 40-metre drop-goal attempts in the last three minutes as the game ended in stalemate.