World No. 2 Alexander Zverev was forced to address previous domestic abuse allegations made against him after he was heckled by a member of the crowd after the Australian Open final on Sunday.

MELBOURNE, Australia — Jannik Sinner beat Alexander Zverev 6-3, 7-6 (4), 6-3 in the Australian Open final at Melbourne Park Sunday. The No. 1 seed prevailed over the No. 2 seed in a match ultimately decided by Zverev’s discomfort when coming forward, Sinner’s underrated first serve, and a kiss of death from the net.

After getting overrun by Jannik Sinner 6-3, 7-6 (4), 6-3 in the men’s singles final Saturday night to give the world No. 1 player a back-to-back victory in Melbourne, fans called out Zverev for his dark past, referencing two of the German player’s ex-girlfriend’s who have accused him of domestic abuse.