Milos Raonic advanced to the third round of the Miami Open tennis tournament in Key Biscayne, Fla., with a win on Saturday.

The Canadian took the match against American Denis Kudla in straight sets, 7-6 (4), 6-4.

Raonic is the sole remaining Canadian in singles action as Vasek Pospisil lost his second round match on Friday, while Eugenie Bouchard's slump continued with a first-round exit earlier in the week.

Nadal calls it a day

Spaniard Rafa Nadal retired during a match for the first time in more than six years when he quit during his second-round encounter against Damir Dzumhur on Saturday.

Sporadic boos greeted 14-times grand slam champion Nadal when he called it a day after seemingly feeling ill during the third set of his encounter in oppressive humidity in south Florida.

The 94th-ranked Dzumhur, of Bosnia, led 2-6 6-4 3-0 at the time, and was up 30-15 on serve. The last time Nadal quit during a match was in a quarter-final against Andy Murray at the 2010 Australian Open.

Nadal said he felt fine before the match and wasn't sure whether he was contracting an illness.

"Hopefully, it's just the extreme conditions," he said. "It's tough for me, because I felt I was playing well. It's a hard accident. That's life."

His departure left the draw without three of the five highest-seeded men. No. 4 Stan Wawrinka lost to Andrey Kuznetsov 6-4, 6-3, and No. 3 Roger Federer withdrew Friday because of a stomach virus.

Other winners of second round matches on Saturday were Japan's Kei Nishikori, Alexander Dolgopolov of Ukraine, American Jack Sock, and Andrey Kuznetsov of Russia.

Serena gets 750th career win

Serena Williams won her 750th career match to stay on track for her ninth Miami Open title when she beat Zarina Diyas of Kazakhstan 7-5 6-3 in the third round in Florida on Saturday.

The world No. 1 improved her career record to 750-125, seventh on the all-time list and just three match wins behind Lindsay Davenport's 753.

Martina Navratilova sits atop the all-time list with 1,442 wins. The 34-year-old Williams will meet Russian Svetlana Kuznetsova in the fourth round.

The 15th seed defeated France's Caroline Garcia 4-6 6-2 7-6(6). Unlike the last time they met, when Williams required 54 minutes and Diyas won just two games, the 22-year-old Kazak gave the American some trouble in the heat and humidity of Miami.

Williams jumped out to a 4-0 lead in the second set, only to see Diyas rally and win three straight games. But the 21-times grand slam champion steadied to close out the match.

"I think she called her coach and they used a different strategy," Williams said in a courtside interview.

Meanwhile, No. 8 Petra Kvitova lost to No. 30 Ekaterina Makarova 6-4, 6-4. No. 3 Agnieszka Radwanska, the 2012 champion, eliminated Madison Brengle 6-3, 6-2.

With files CBC Sports and The Associated Press