MIAMI (AFP) — World No. 2 Aryna Sabalenka returned to the court for the first time since the death of her former boyfriend earlier this week and kept her emotions in check as she beat Spain's Paula Badosa 6-4 6-3 on Friday.

After six hours of rain delays, Sabalenka walked onto the court wearing an all-black outfit, a choice matched by her close friend Badosa.

Two-time Australian Open winner Sabalenka said she was "heartbroken" by the death of former boyfriend Konstantin Koltsov in a statement on Wednesday, where she revealed they had not been a couple at the time of his death.

Koltsov died on Monday with Miami police saying he had jumped from the balcony of a room at an resort in an "apparent suicide."

The former National Hockey League ice hockey player and coach was 42-years-old.

Sabalenka made a slow start to the match but broke to go 4-3 up in the first set and never looked back from that point on.

The Belarusian then broke in the third game of the second set with a superb cross court forehand winner and showed too much power for her Spanish opponent as she wrapped up the win in one hour 22 minutes.

The two players embraced at the net before leaving the court without an on-court interview. Sabalenka has asked the WTA to be excused from media duties at the tournament.

Badosa said she was not surprised by the way Sabalenka was able to maintain her focus and deliver a solid performance.

"She is a very, very strong woman with a strong personality. You can see it on the court. I know her off court so it doesn't surprise me at all," she said.

"I knew she was going to play very well or like normal. I told her I wish her the best and let's see if she can go deep in this tournament."

Badosa had said before the match that she expected it to be "uncomfortable"  playing against Sabalenka given her friendship with the Belarusian.