AFTER a shaky start to the season, Glasgow Warriors needed a timely boost as they head into the Heineken Champions Cup. Thankfully for them, the returning World Cup players have provided just that.

Only Jonny Gray, the lock on an extended break after Japan, is likely to be out of contention for a place in the opening European game on Saturday, when Sale Sharks visit Scotstoun.

So, with a squad close to full fitness, Jason O'Halloran, the attack coach, expects his side to build on the momentum of good wins in the past two weeks.

While the overall injection of international class has been a factor in that, he was happy to point to two of the more fringe players from the World Cup squad as being the key to Glasgow's transformation.

"Adam [Hastings, the fly-half] and George [Horne, the scrum-half] have been pivotal – really enthusiastic and accurate, and they've brought a lot of tempo to our game which was perhaps lacking early doors," he said.

“I know that with Gregor [Townsend, the Scotland coach] lately, they have had a real focus around their kicking game and trying to develop that a lot more. Adam’s tactical control has been a lot improved since he’s come back.

"Even against the Kings the week before, a couple of early kicks, which put them deep, were pivotal to us getting on the front foot.

"He’s known as a running 10 but his tactical ability with the boot has really improved.

"That’s crucial because we can’t be a team that just pings the ball around east to west all day long.

"We are going to get knocked over and that’s going to put pressure on us. We’ve got to manage that middle third effectively, which he’s done."

It is not just the half-backs who have impressed O'Halloran, however. He has seen the impact of the international players in all departments and, with Sale likely to rest all the players in their squad who were in action over the final weekend of the World Cup, that could be a crucial advantage.

"I though Ryan [Wilson, the No.8] was really good at the weekend, Zander [Fagerson, the prop] has been fantastic too. Almost to a man those guys have brought a real edge that has helped us to speed the game up, which is important to the way we want to play," O'Halloran said.

"Zander had 16 carries – that's massive. Fraser [Brown, the hooker] had 16 or 17 carries as well. Matt Fagerson was the other one – among those three guys they had almost 60 carries.

"That was crucial to our ability to maintain ball and create a lot of pressure through multiple phases, something that really let us down in the first four games when we conceded a lot of ball at breakdown.

"It is massive to the way we want to play the game. We feel like we’re fit but you can’t impose your fitness on teams if you can’t look after the ball for long enough – that’s been a big change in the past fortnight."

Europe remains the big void in the Glasgow performance record.

Over 24 season they have reached the quarter-finals only twice, both times after finishing second in their pool and being comfortably beaten by Saracens in the knockout game.

This year they have a chance to start strongly before they travel to Exeter and a date with Stuart Hogg's new team, but O'Halloran is wary of the challenge.

"It’s a typically like a boxer’s punching scenario – they think they can bully us, we think we can outmanoeuvre them with our pace," he said. "Both teams will want to establish their game. It’s up to us to ensure it is us who do that."