Hull KR survived a scare to beat winless London Broncos on Sunday but head coach Craig Sandercock was left sweating over Kris Keating's fitness.
Keating, who joined Hull KR from NRL outfit Canterbury Bulldogs this year, didn't emerge after half time after sustaining a thumb injury.
In Keating's absence, Craig Hall came off the bench to score twice as Hull KR pulled clear to win 48-16 and former Manly-Warringah coach Sandercock was impressed with the 26-year-old's display.
However, he conceded Keating would be a big miss going forward, leaving him with a nervous wait for the scan results.
"Kris Keating is a pretty important player for us and we need to keep our fingers crossed that the scan comes back in our favour," Sandercock said.
"He has done something to his thumb. It is definitely not broken - it is more ligament damage and it depends on how bad it is."
There were, however, plenty of positives for Hull KR, who ran in six tries to ensure the Broncos are still on the hunt for their first Super League points of the season.
Former Newcastle Knights forward Neville Costigan crossed over to score and Sandercock is impressed with the way he and countryman Michael Weyman are marshalling the pack.
"They are outstanding," he added. "Their leadership and the way they are playing is vital for us.
"London should have beaten Catalan last week - I was very impressed with them and they have got a bit of continuity now. At 22-16 it was touch-and-go there so I am very pleased with the boys.
"We switched off after half time and we paid the consequence. When it got to 22-16 it was anyone's game but it was a good response from us in the end and we played a lot smarter in the last 20 minutes or so."
Former NZ Warriors man Lance Hohaia and Kiwi-born forward Mose Masoe each crossed over to score as St Helens kept up the pressure on leaders Leeds Rhinos with a 41-22 win against Huddersfield Giants on Friday.
They had slumped to defeat against Warrington Wolves in their previous fixture and head coach Nathan Brown was satisfied with their efforts this time around.
"The response to last week's game and the manner of which we started the game was obviously quite pleasing from a defensive point of view," said Brown.
"The effort and commitment for each other great and the score probably flattered the opposition. I thought it was our best performance against good opposition for a while.
"I'm pleased how we got the physical part of the game right.
"It doesn't mean we're the finished article, we have got to keep working hard and we've got to deliver that type of performance next week."
Warrington, meanwhile, backed up that win against St Helens by sinking Wakefield Wildcats on Sunday.
Head coach Tony Smith was impressed with his squad, which was packed full of home-grown talent, and New Zealander in prop Roy Asotasi.
"We had 16 British players out there - just one overseas player in Roy Asotasi - and a fair amount of those were young British players as well. So I'm pleased with that, it's a fairly good stat that one," said Smith.
"They had a real dig at us, so to soak that up and come back with some of the quality tries was also good."