Tennis news today: Naomi Osaka and Daniil Medvedev progress in Miami, Iga Swiatek surpasses Rafael Nadal's win tally

Naomi Osaka and Daniil Medvedev have both progressed to the next round of the Miami Open. The Japanese received a walkover to the last 16 after Karolina Muchova withdrew from their match while Medvedev beat Andy Murray 6-4, 6-2 to reach the third round.

Emma Raducanu has responded to critics who say she is not focused on tennis. The Brit stated that she practices hard every day but that people question her dedication after one social media post.

Iga Swiatek, meanwhile, has the highest number of wins this season, surpassing her idol Rafael Nadal.

Here's a look at the biggest news of the day.

Naomi Osaka and Daniil Medvedev win in Miami

Naomi Osaka reached the fourth round of the Miami Open

Naomi Osaka booked her place in the last 16 of the Miami Open on Saturday without even hitting a ball as Karolina Muchova pulled out of their third-round match. The Czech, who returned to action for the first time since last year's US Open, said the two matches she played in Miami were too much for her body. She also stated that she would return for the claycourt season.

"I'm sad that I cannot put up a battle against Naomi today. After a long break from tennis, 2 tough matches in row have been a lot for my body and I need longer to recover. Was nice to be part of the Miami Open again! I will be back on clay!" Muchova tweeted.

Osaka will square off against Alison Riske in the fourth round of the Miami Open.

Daniil Medvedev, meanwhile, won his second-round match against Andy Murray 6-4, 6-2. The Russian will face Pedro Martinez in the third round.

Emma Raducanu responds to criticism over sponsorship deals

Emma Raducanu, who recently became Porsche's brand ambassador, hit back at criticism that she isn't focusing enough on tennis. The teenager said that despite her sponsorship deals, tennis is still her top priority.

“Maybe you just see, on the news or on social media, me signing this or that deal and I feel like it’s quite misleading because I’m doing five, six hours a day [of training], I’m at the club for 12 hours a day," Raducanu said.

"But I throw out one post in the car on the way to practice and all of a sudden it’s ‘I don’t focus on tennis’. I think that it is unfair but it’s something I have learned to deal with and become a bit more insensitive to the outside noise. I feel like my days [with sponsors] are pretty limited. I’m not doing crazy days. I’m doing three, four days every quarter, so it’s really not that much.”

Iga Swiatek surpasses Rafael Nadal for most wins this season

Iga Swiatek will become the new World No. 1 after her comprehensive victory over Viktorija Golubic in the second round in Miami. The win was the Pole's 21st of the season, which is more than any other player, male or female.

Swiatek surpassed Nadal, who has won 20 matches this year. The Pole is currently on a 12-match winning streak and has won back-to-back WTA 1000 titles in Qatar and Indian Wells.

Top players like Roger Federer do not play for the money" - Jessica Pegula

World No. 21 Jessica Pegula stated that she plays tennis for the love of the game and not for financial reward. The American also pointed out that top players do not play for money and cited the example of Roger Federer, who is still around at the age of 40.

"You see the top players, they're not playing really for more money at the time. They have already made enough money. Look at Federer. He could have stopped a while ago and nobody would have blamed him. He says he loves the sport. I feel like I have the same feeling. I'm very compassionate about it and I love to compete and I love the challenge and the grind of doing that," Pegula said.

Nick Kyrgios speaks out on Jenson Brooksby's ballboy incident

Nick Kyrgios gave his two cents on the Jenson Brooksby controversy during the Miami Masters. The American threw his racket in anger, nearly hitting a ballboy. Brooksby was fined $15,000, which was less than what Kyrgios had to cough up for a similar incident in Indian Wells.

The Australian did not criticize Brooksby, instead saying that everyone has made a "questionable decision" at some point in their lives.

"I mean, look, I have done plenty of things in my tennis career and in my life that, you know, I think everyone has where they have made a questionable decision, whether it's tennis, whether it's your job, whether it's life, whether it's a relationship, we have all made questionable decisions. No one is perfect," the Aussie said.

He also gave Brooksby credit for owning up to his mistake and said he never "meant any harm."

"I think, like everyone knows, he held himself accountable. He knows it's not the right thing to do," Kyrgios said. "I can't see him being a personality where he's going to kind of say, F-you, like it's not-okay-type thing. I don't think that's the right way to go about it, as well. Obviously it's not right, but he didn't mean it. I don't think he meant any harm."

Veterans Rafael Nadal and Andy Murray both felt the ATP needed to take a stronger stance with regards to such incidents, especially since they are increasing in frequency.

“The problem is, in my opinion, when you allow the players to do stuff, then you don't know where the line is. And it's a tricky thing. But probably because these situations are happening more and more often, the ATP should review things and make decisions,” Nadal said.