WATCH: Alexander Zverev complains when a feather delays play at the Australian Open

MELBOURNE, Australia (AP) — Alexander Zverev got bothered by a bird’s feather at the Australian Open and was warned for cursing during his quarterfinal against Tommy Paul.

The second-seeded Zverev was down a break in the second set—a set he went on to win—when Paul saved two break points. With the game in the balance, chair umpire Nacho Forcadell called a let and ordered a replay of a point when he saw a white feather drop into Zverev’s eyeline as the German player was in his backswing.

“What? A feather? There’s millions of them on the court,” Zverev said as he approached the official while holding up the feather.

Zverev grasped the net to pause for a while before going back to work, but Paul soon held serve.

Zverev was already heated earlier in that game, when a spectator yelled “out” during a point. Zverev complained about it to Forcadell, who asked the crowd not to shout during points. After losing the next point, Zverev was warned about showing too much frustration.