The visitors initially took control of proceedings, with Robert Andrich particularly feeling the Gunners’ pressure as he was booked inside two minutes for pulling down Viktor Gyokeres.
Christian Kofane still caused issues going the other way and helped Die Werkself grow into the game, although David Raya routinely saved the 19-year-old’s speculative shot from range, and Ibrahim Maza fired harmlessly off-target from his lay-off.
With things becoming more open, Gabriel Martinelli smashed a shot against Janis Blaswich’s crossbar at the end of a swift Arsenal move, before Gabriel Magalhaes bravely blocked an attempt from Jarell Quansah.
Returning to his parent club, Piero Hincapié saw his shot from a tight angle saved, but with so much at stake, there was more of a combative nature to the action rather than a creative spark as the first half progressed.
That was epitomised shortly before the break when Exequiel Palacios stopped Bukayo Saka in his own box and released Kofane, who was then halted by Gabriel and William Saliba.
Die Werkself’s kick-off routine saw Martin Terrier’s header bring a superb save out of Raya, but there was nothing the visiting goalkeeper could do from the ensuing corner as Andrich was afforded the space to head home within a minute of the restart.
Hincapié couldn’t find the target with his header from a Declan Rice free-kick on the hour mark, as Arsenal tried to ask more questions with Noni Madueke replacing Saka in the aftermath of that attempt.
The hosts still looked relatively comfortable for large periods, even when Jurrien Timber headed over the crossbar.
That comfort crumbled, though, as Malik Tillman conceded a penalty when he slid in on Madueke, and Havertz duly converted from the spot despite Blaswich diving the right way, levelling the tie against the club he spent a decade with.
That moment leaves the tie perfectly poised heading into the second leg, while also forcing Leverkusen to settle for a fourth draw from their last four matches across all competitions and extending Arsenal’s unbeaten run to 12 matches.
Flashscore Man of the Match: Exequiel Palacios (Bayer Leverkusen)
