The Gunners started the game well and created a number of good opportunities to score in the opening stages of the game. However, they failed to make the most of them and BATE punished Unai Emery's side for not taking their chances by taking the lead through Stanislaw Drahunin in the 45th minute of the game.
Arsenal tried their best to cut the deficit post half-time and created a host of clear-cut opportunities. However, the hosts' defence stood strong and didn't let the Londoners take anything away from the game.
To make things worse for Arsenal, Alexandre Lacazette was sent off late in the game, meaning that he would miss the 2nd leg at the Emirates.
Unai Emery's team enjoyed 77% of possession during the game and had 16 shots on goal as compared to BATE's six.
The Gunners are now struggling after a promising start to the season under their new manager Unai Emery, and are currently fifth in the Premier League table. They tried to strengthen their squad during the January transfer window, but lack of funds prevented them from completing their objective.
On the other hand, BATE are the most successful team in the Belarusian football history and were crowned as the Champions of Belarus for the 15th time in December. They are only team from Belarus to have qualified for the group stage of the UEFA Champions League and will again try to repeat that feat when they take part in the Champions League qualification stages next season.
Football fans on Twitter reacted with plenty of humor and wit to Arsenal's defeat, and here are some of the best tweets.