Adam Ashe went over or two tries

Tries from Adam Ashe and George Horne and the boot of Adam Hastings put Warriors 20-10 up at the break - Toby Arnold replying for the hosts.

In the second period Noa Nakaitaci and Charl McLeod also crossed but tries from Stuart Hogg, Huw Jones and Ashe took Warriors clear. Adam Hastings ended up with 17 points while half-back partner George Horne took the man-of-the-match award.

The win puts Warriors a point ahead at the top of Pool Three with rivals Saracens hosting Cardiff Blues on Sunday.

Both teams went into the match knowing victory was vital to keep the European hopes alive and an entertaining first 15 minutes saw both sides swap penalties through Hastings and Jonathan Pelissie.

Arnold broke clear to show Lyon's danger, but with heavy rain having fallen, it was no surprise to see the boot dominating the game.

Despite some slippery turf, Hastings nailed a second kick and Glasgow then moved further clear with a fine team try. Hogg, Tommy Seymour and Callum Gibbins were all involved.

When the ball was recycled, scrum-half Horne spotted the lack of a Lyon ruck guard and popped the ball up for Ashe who scored. Hastings converted.

Lyon hit straight back. Glasgow were penalised for a forward pass and from the platform they were given, the hosts spread the ball left where Arnold an easy finish.

Pelissie, who had missed an earlier penalty, added the touchline extras.

Just before the break, Glasgow came close to a second try. A sensational Nick Grigg break saw him storm clear and although the first chance was wasted, Horne's dynamism again came up trumps.

The forwards did all the hard work and Horne ran straight through the ruck to score. Hastings kicked the goal for a 20-10 interval lead and the ideal end to the first period.

Hastings booted a three-pointer soon after the game's resumption, but when Lyon intercepted a Jonny Gray pass, they went the length of the field. Grigg was penalised but had not been released in the tackle and from the quick tap, Nakaitaci crossed in the left corner for an unconverted score.

The tit-for-tat nature of the encounter continued as Glasgow hit straight back with their third try as Hogg crossed. Peter Horne chipped through and Lyon replacement Charl McLeod could not ground.

The ball bounced loose and it was Hogg who got downward pressure for a try given via the TMO.

Hastings missed his first kick of the day, but then set up Jones who scored with his first touch of the ball as Glasgow pounced on a Lyon turnover.

It was the crucial fourth try, but the scoring continued. Tim Swinson was yellow carded for a professional foul and Lyon's power game allowed McLeod to get one back.

Jean-Marc Doussain converted, but Ashe had the last word by crashing over late on from the back of a scrum.

After the mach Dave Rennie said: "We're not going to look too far ahead. What we know is if we get it right next week we'll put ourselves in a strong position heading into the last couple of rounds in January, starting with Cardiff at home.

"We're desperate to still be in the mix come the knock outs and we've got some tough games coming up."

Rennie made 12 changes to the starting XV for this game and will have to make another tough selection decision ahead of the return fixture next Saturday.

He said: "We'll put a very strong side on the field next week, there will be changes.

"There's not an awful lot between a lot of our boys and we want to reward performance and provide opportunities.

"There will be a handful of changes but we'll be putting out a good a side as possible to get the job done."

Adam Ashe is one player Rennie admitted was "playing too well to drop" before this tie and the back-row scored two tries in another impressive performance.

Rennie said: "We're rapt for Adam, he got a couple of dot downs, but it was all the other work he did defensively; carrying creative forward and so on. He was a big contributor today."

Despite the victory and positive performance Rennie refused to get carried away and addressed a few areas of the game that his side will need to improve on next weekend.

"We were disappointed to go down to 14 when Tim Swinson saw yellow, I don't think our discipline was that flash today and while you can debate the odd penalty, some of them were poor decisions on our part that put us under pressure.

"We've played with 14 recently and we know how to maintain ball in those situations and I thought the boys controlled that period pretty well.

"We only gave away 6 penalties last week, and in the last few weeks we've kept the count to single figures. So that aspect of the game is disappointing, and we kicked away too much ball giving them a lot of opportunities to attack us. It's something for us to look at and be better at next week.

Recovery will be crucial now for the Warriors after a physical encounter on a muddy pitch at the Stade de Gerland.

Rennie said: "It's a beautiful stadium but the pitch is pretty heavy, the ground was getting churned up at every scrum.

"We're used to a firm surface at home so we've got some pretty tired legs especially because it was such a physical game. Lyon like to play a lot of footy and they challenged us all over the park."