Paris - Arsenal face an uphill battle to progress in the Europa League after a 1-0 defeat by BATE Borisov in the last-32 first leg which saw Alexandre Lacazette sent off on Thursday.
Stanislav Dragun put BATE ahead just before the break in Barysaw and Arsenal never threatened an equaliser, with Lacazette's late dismissal also ruling him out of next week's return game at the Emirates.
Unai Emery's side have now won just two of their last nine away matches - last weekend's victory over the Premier League's bottom club Huddersfield and an FA Cup win against third-tier Blackpool.
Arsenal enjoyed plenty of the ball in the opening stages, but it was the hosts who almost grabbed the lead as debutant Nemanja Milic flicked Igor Stasevich's cross onto the outside of the post.
The visitors' best chance in the first half fell to Lacazette, only for the Frenchman to head over when unmarked at the back post.
BATE made him pay when they snatched the advantage on the stroke of half-time as Dragun climbed highest to send a header from Stasevich's free-kick looping into the top corner.
Arsenal were struggling on a difficult pitch in Belarus, and even when Lacazette did find the net just before the hour mark, he was rightly flagged offside.
Emery, who won three consecutive Europa League titles with Sevilla from 2014-2016, threw on Pierre-Emerick Aubameyang, Lucas Torreira and Denis Suarez in an attempt to find a breakthrough.
But Arsenal continued to labour and their night took another turn for the worse as Lacazette was sent off for lashing out at Aleksandar Filipovic with his elbow in the 85th minute.
Elsewhere, Inter Milan claimed a 1-0 win at Rapid Vienna despite Mauro Icardi snubbing the trip after being stripped of the captaincy over a contract row, with Lautaro Martinez scoring the winner from the penalty spot.
Wissam Ben Yedder's 22nd-minute strike helped record five-time winners Sevilla take a large step towards the last 16 with a 1-0 victory over Lazio in Rome, while Benfica backed up their 10-0 weekend thrashing of Nacional by winning 2-1 at Galatasaray.
Hatem Ben Arfa netted a penalty but Rennes twice blew a two-goal lead to draw 3-3 with Real Betis in France, while Olympiakos were held to a 2-2 home draw by Dynamo Kiev.