Nemanja Milunovic's header has cancelled out Admir Mehmedi's fourth-minute opener, as Bayer Leverkusen go into half time all square with BATE Borisov.
The Bundesliga side took the lead in the opening minutes through Mehmedi, as the Swiss international drilled home his shot after some confusion amongst the Belarusian defence.
However, the visitors responded 10 minutes later through Milunovic, who headed home BATE's only chance of the game from a corner, with the goal coming against the run of play.
Leverkusen continued to dominate the rest of the first half but the away side stood firm and held out until the half-time whistle.