Theo Fages played a starring role as St Helens beat Warrington Wolves 25-22 to inflict only a second defeat of the season on the Super League leaders.
The Wolves lost influential scrum-half Chris Sandow - Super League's stand-out player so far this term - to a hamstring injury in last week's win over Wigan Warriors.
And although Stefan Ratchford impressed for Warrington in Sandow's absence, it was a Saints half-back who shone brightest on Friday, Fages having a hand in two tries as his side became the first team to win at the Halliwell Jones Stadium in 2016.
The hosts led 10-0 early on through tries from Kevin Penny and Ryan Atkins, but Kyle Amor and Jack Ashworth responded for Saints - the latter taking a short pass from Fages to score his first Super League try.
Ben Currie's try on the stroke of half-time ensured Warrington led 14-12 at the break, yet that was as good as it got for Tony Smith's men as Fages laid on another score for Matty Dawson before Morgan Knowles got on the end of a deflected grubber kick from Luke Walsh.
Warrington refused to give in and reduced their deficit to three points through late tries from Penny and Tom Lineham, but Saints held on to close within four points of top spot.
In Friday's other Super League fixture, Hull FC beat rock-bottom Huddersfield Giants 37-20 to record a fifth win in succession.
Full-back Jamie Shaul claimed two tries for in-form Hull, who pulled clear after taking a slender two-point lead into the interval.