St Helens full-back Jonny Lomax scored two tries after a 13-month absence with a knee injury to help Saints to a thrilling win over Leeds Rhinos.
It took just five minutes for Lomax to score with Joe Greenwood and Lomax’s second making it 16-16 at the break.
After Kyle Amor’s score, Ash Handley’s try put champions Leeds ahead for the first time.
However, another from Greenwood and two tries by Theo Fages for Saints held off a late fightback by the Rhinos.
The win ends a three-game losing streak for Keiron Cunningham’s side at Langtree Park and moves them up to fifth in Super League.
Lomax, 25, suffered his first serious knee injury in June 2014 and required another reconstruction last year that ruled him out for the season.
Leeds, whose try scorers included Ashton Golding, Rob Burrow, Jimmy Keinhorst (two) and Anthony Mullally, have now lost five of their last six games and sit 10th.
Their miserable start to an injury-hit season has seen them win just three of 12 matches in the defence of their title.
St Helens coach Keiron Cunningham:
“It was quite an emotional night for me with Jonny and Percy (Mark Percival) and those boys coming back, especially Jonny.
“I’ve been there with Jonny for a long period of time and we have a really close affiliation. Just to hear the Saints fans in full roar when Jonny goes over for that try, it brings a tear to your eye.
“It meant a lot to me and to the fans to see the kid in a Saints shirt again, seeing what it means to Jonny to get through it fine is immense.
“He’s not played for 15 months and he just kept going. We did roll him in a few different positions to try and freshen him up but all credit to Jonny, he did a great job and had an influence on the game from the start to the finish.”
Leeds Rhinos coach Brian McDermott:
“I’ve experienced some great moments with this team and for different reasons, I feel so good about the group and where we’re at, although if you look at the league position, it’s another loss and we’re no further up the ladder and that’s hard to take.
“The harsh reality is we’ve got to win some games but, if don’t get what we want to get this year, we’ll go down swinging.
“I don’t think either coach will be happy defensively but some blokes were gassed and it’s starting to bite a bit.”
St Helens: McDonnell; Lomax, Dawson, Percival, Owens; Fages, Walsh; Tasi, Roby, Amor, McCarthy-Scarsbrook, Greenwood, Wilkin.
Replacements: Walmsley, Vea, Richards, Knowles.
Leeds: Hardaker; Golding, Watkins, Keinhorst, Handley; Lilley, Burrow; Galloway, Falloon, Garbutt, Ablett, Delaney, Jones-Buchanan.
Replacements: Sutcliffe, Singleton, Achurch, Mullally.