Australian full-back Lachlan Coote scored two of St Helens' seven tries and kicked six conversions for a 20-point haul as Justin Holbrook's men pulled 10 points clear of Warrington with their 40-12 thrashing of Hull FC.
The leaders brushed off the absence of skipper James Roby as well as back-up hooker Aaron Smith, with James Bentley proving a useful operator around the rucks.
"Coote was tremendous and I thought James Bentley was enormous for us," said Holbrook. "To step in at nine and play 80 minutes defend so well, I'm real happy for him.
"It's a tough place to come and play, with a hostile crowd, so to come away with a good win like that, I'm really happy.
"It was a really good performance from us. There are areas for improvement for sure but it was a dominant win.
"We know how dangerous an attacking side Hull are so to keep them scoreless for long periods of the game was fantastic."
Holbrook says both Roby and Smith could be available for the visit of Wigan next Friday.
Hull coach Lee Radford says his key players need a change of mindset if they are to avoid their Super League season petering out.
Radford hit out after watching his third-placed side go down at home, a week after being humbled by relegation-threatened neighbours Rovers in the Hull derby.
Hull trailed 40-0 before producing a late fightback that brought tries for Jamie Shaul and Ratu Naulago but it was scant consolation as they crashed to a fifth home defeat of the season.
Radford's men have conceded 102 points at the hands of St Helens so far this year and the bad news for the Black and Whites is that these two sides meet for a third time in September.
"It was a self-inflicted loss in many ways, very similar to last week," Radford said. "The only difference is that last week we were playing the bottom of league and this week we were playing the top of the league.
"How we go about our business in terms of building the foundation of a game, the penny has got to drop for our pivotal players real soon. We've got to learn quickly or it's going to be a long finish to the season.
"There's a process you've got to go through to beat any side and for the last two weeks we've not gone through that process.
"We play a no-frills team next week in London who will compete at 80 per cent and, unless some blokes change their mindset, we're going to face a similar result to tonight.
"So it's my job this week to try and convince some of the key men who get us around the park to believe in that."