Glasgow Warriors were edged 20-13 by runners-up La Rochelle in their European Champions Cup opener.

Reda Wardi had scored the first for La Rochelle, with Eneriko Buliruarua soon cancelling out Steyn's effort while Rory Darge was in the sin bin.

Glasgow earn a losing bonus point and host Exeter Chiefs next Saturday.

They will almost certainly need to conquer the English giants, who have Scotland internationals Stuart Hogg, Jonny Gray and Sam Skinner among their ranks, to stand a chance of reaching the last 16.

Returning to the ground where they won 27-24 two years ago, Glasgow made a fine start as they kept the ball alive for almost two minutes from the kick-off to put the home side under immediate pressure.

Their brave approach meant they enjoyed 64% possession in the opening quarter and led 6-0 thanks to two penalties from young pivot Ross Thompson.

The Glasgow stand-off had a third shot from long distance, but failed to hit the mark.

La Rochelle finished the first half strongly and took the lead just after the half-hour mark when prop Wardi was driven over from a 5m line-out.

Ihaia West added a wide-angled conversion and then stroked over a 40m penalty to give his side a 10-6 lead at the break.

West was just wide with a 52m monster attempt at the start of the second half, but it was Glasgow who picked up the first points after the break.

Having earned a penalty in front of the home posts five metres out, they turned down the automatic three points and went for a tap penalty.

George Turner led the charge and their bravery was rewarded when skipper for the day Ali Price chipped across the try line to allowed Steyn to rise highest and then ground the ball.

Thompson kept his nerve to add the extras from the right and - with 50 minutes gone - Glasgow were back in the lead.

To stay there they needed to keep the power-laden home pack at bay and their cause was dented when they lost Darge to a yellow card for collapsing a driving maul five metres out.

La Rochelle went for a scrum and fashioned a try in the right corner for Fijian win Buliruarua, while West converted off the touchline and then added a penalty soon after as the home side celebrated their victory.

Glasgow mindset lacking - reaction

Injured Glasgow Warriors co-captain Fraser Brown on BBC Radio Scotland

For the first 25 minutes, Glasgow were the better team by far. The energy and work rate then went, for whatever reason.

Their intensity never really got back up there. A lot of their errors came from not working hard enough, early enough to get set.

It's a mindset. On those occasions, it was almost like some players were expectant of others to do their job, and when there was a missed tackle or they got stepped, they were already on the back foot.

In that last 20 minutes, I was disappointed by the energy and impact on the bench. With a six-two forwards and backs split, you're looking for that forward pack to really take the game to La Rochelle.

It was a little underwhelming. The last five, 10 minutes summed it up for me. Good ambition to keep playing, but not working anywhere near hard enough to get into the right positions.

We were quite away from our best, but we should have done enough to win that game. We had enough opportunities.

La Rochelle: Dulin, Favre, Sinzelle, Botia, Retiere, West, Kerr Barlow; Wardi, Bourgarit, Atonio, Sazy, Skelton, Boudehent, Vito, Alldritt (capt).

Replacements: Lagahe, Priso, Herrera, Lavault, Bourdea, Popelin, Buliraura, Danty.

Glasgow Warriors: McKay, Steyn, Tuipulotu, Johnson, McLean, Thompson, Price (capt); Kebble, Turner, Z Fagerson, Cummings, Gray, M Fagerson, Darge, Dempsey.

Replacements: Matthews, Bhatti, Pieretto, Bean, Harley, Miller, G Horne, Weir.

Referee: Ian Tempest (Eng)