Highlights: Atletico Madrid 2-1 RB Leipzig
Conor Gallagher came on as a substitute as Atletico Madrid scored a 90th-minute winner against RB Leipzig in their Champions League opener.
Benjamin Sesko headed the German visitors into a fourth-minute lead, before Antoine Griezmann equalised after 28 minutes with his 37th goal in the competition.
France World Cup winner Griezmann scored from 12 yards with a volleyed effort and was denied a second goal by a fine save from RB Leipzig keeper Peter Gulacsi.
It was Griezmann who set up the dramatic late winner as his cross picked out Jose Maria Gimenez for a downward header into the net.
England midfielder Gallagher, who moved to Atletico in August for about £33m, came on in the 63rd minute with the game 1-1.
He is the second English player to feature in the Champions League for Atletico after Kieran Trippier.
While RB Leipzig host Juventus next in the competition on 2 October, Atletico Madrid are away to Benfica on the same date.
'He's a free spirit' - pundits analyse Griezmann's contribution
Watch highlights of every Champions League game from 22:00 on Wednesday on BBC iPlayer and the BBC Sport website and app.
There will also be a Champions League Match of the Day on BBC One on Wednesday, from 22:40 to 00:00.
