The 23-time Grand Slam champion teased Dimitrov from the commentary booth.

The 23-year-old American kicked off his Miami Open campaign Friday, winning eight of 11 net points during his 6-2, 6-2 win over countryman Marcos Giron.

Look for Dimitrov to put an end to Musetti's run in Acapulco, while Karatsev should keep things close against Rublev in Dubai.

Djokovic and Zverev floated the idea of an NBA-style bubble, with multiple events held in one location. "If we stop the tour," Nadal said, it would be difficult to restart and "a lot of jobs gonna suffer a lot. I mean, not only players."

Russian qualifier Aslan Karatsev continued his fairytale run at the Australian Open, outhitting a hampered Grigor Dimitrov in four sets to become the first man to reach a major semifinal in his main draw debut.

It's been a miraculous week of tennis for the world No. 114, but it will likely come to an end at the hands of Dimitrov's backhand slice.

The former world No. 3 pulled away from last year's Australian Open finalist, 6-4, 6-4, 6-0, on Sunday to reach his fourth quarterfinal at Melbourne Park.