GLASGOW made things difficult for themselves in this first Champions Cup game of the season, and after leading 13-0 at the break might well have been punished for a slack second half.

But, while far from perfect, on the whole this performance was the calmest and most mature that Dave Rennie’s side have put in this season, and although they will have to improve again when they visit Exeter Chiefs in their next Pool Two game on Saturday, they know they are heading in the right direction.

“I thought first half we were really good, maybe even better than the 13-0 scoreline,” the head coach said after a match in which DTH van der Merwe scored his team’s only try and Adam Hastings added the other points with a conversion and two penalties.

“We applied a lot of pressure, but the second half was disappointing.

“We talked a lot about controlling territory, forcing them to play from deeper, but we didn’t do that well enough. I just thought we overplayed down our end of the field.

“But having said that, our line-out was excellent, our defence line-out was excellent, likewise with the scrum. The big men put in a shift and that got us home in the end.”

Rennie knows the scrum, the defence, the line-out and the rest will all have to be excellent again next week at Sandy Park, and that against stronger opposition – Sale having been without key players such as South Africa’s World-Cup-winning scrum-half Faf de Klerk – there will be less chance of mistakes going unpunished.

“I think it’s just about control for next week,” he added. “I just think we’ll maybe need to play a little bit smarter next week and improve the quality of our kicking.”

The first half took a long time to get going, as the Sale defence held up well in the face of persistent pressure from the home team. Hastings was off target with a 10th-minute drop-goal attempt as Glasgow tried to turn that pressure into points, but five minutes later he put his team ahead with a penalty from the 10-metre line.

The stand-off missed his next attempt, but 3-0 then became 6-0 after 25 minutes when he was on target with a third penalty. That lead was no more than the Warriors deserved, and they then gave the score a more accurate reflection of their superiority with a try five minutes before half time.

George Horne, a constant danger on the break, began the move off the blindside of a scrum. He passed to Sam Johnson, and the centre swivelled then passed to van der Merwe, who slipped through the first tackle then beat the remaining two defenders to touch down close to the left corner.

Hastings’ conversion made it 13-0, but there was still a feeling at half time that Glasgow would need the first score of the second half to wrap the game up.

They almost got it after 55 minutes when the stand-off’s kick to the left corner bounced just out of reach of Van der Merwe, but with that chance gone they took their foot off the gas again.

Sensing they were still in the fight, Sale steadily fought back, and got right back into the contest with a try just past the hour. A scrum on the edge of the Warriors 22 gave the visitors a decent platform, and an attack off the base ended with substitute Coenie Oosthuizen forcing his way over the line. AJ MacGinty converted to make it 13-7.

With time running out, Glasgow bossed possession for a long spell and for a time looked like preparing for a drop goal which would have taken the game beyond Sale and denied them a losing bonus.

But then they gave away a penalty well inside the final minute, and conceded another which saw Sale advance to just outside the home 22. That was the ideal position from which to launch a match-winning attack, but a knock-on ended their attack, allowing Glasgow to kick the ball dead.

On another day, the visitors might well have snatched the victory, although Steve Diamond, their director of rugby, accepted that they had not really deserved to do so.

“I thought we could have got a little bit more out of it, but at the end of the day it was probably a pretty fair result,” he said.

“Our line-out performance was very disappointing. We just couldn’t get a foothold anywhere in the game.”

Scorers, Glasgow – Try: Van der Merwe. Con: Hastings. Pens: Hastings 2.

Sale –Try: Oosthuizen. Con: MacGinty.

Glasgow Warriors: T Seymour; R Tagive, N Grigg, S Johnson, D van der Merwe; A Hastings, G Horne; O Kebble, F Brown, Z Fagerson, R Harley, S Cummings, R Wilson, C Gibbins (captain), M Fagerson. Subs: G Turner, A Allan, D Rae, T Swinson, C Fusaro, A Price, P Horne, K Steyn.

Sale Sharks: S Hammersley; M Yarde, C Redpath, L James, B McGuigan; A MacGinty, E Papier; R Harrison, R Webber, J Cooper-Woolley, B Evans (captain), J Phillips, J-L du Preez, B Curry, D du Preez. Subs: A Van der Merwe, C Oosthuizen, W John, M Postlethwaite, J Ross, G Warr, R du Preez, C Ashton.

Referee: A Ruiz (France).

Attendance: 7,351.