KEY BISCAYNE, Fla. — For Roger Federer and Rafael Nadal, it was a happy anniversary.
For Stan Wawrinka, it was not a happy birthday.
Federer and Nadal — playing back-to-back on stadium court on the 13th anniversary of their very first match — both advanced Tuesday to the quarterfinals of the Miami Open, surviving strong tests in both cases.
Wawrinka wasn't as fortunate, the No. 1 seed getting bounced on his 32nd birthday by teenager Alexander Zverev.
"Every match is going to be tough from now on," said second-seeded Kei Nishikori, who also survived a three-setter to reach the quarters.
That seems to already be holding true.
The fourth-seeded Federer outlasted No. 14 Roberto Bautista Agut 7-6 (5), 7-6 (4), the fifth-seeded Nadal got past Nicolas Marut 6-4, 7-6 (4), and Nishikori — a finalist at Key Biscayne a year ago — rallied from a break down in the final set to beat Federico Delbonis 6-3, 4-6, 6-3.
Federer is 16-1 this year, matching his career-best record at this point in a season.
"Is it the best I've ever played?" Federer said. "For me, it's hard to say yes to that question. ... Maybe on the offensive side, overall, I think I'm doing definitely a few things better than I ever have. I do feel that I have improved. The game has evolved, I had to adjust, but overall I do believe I'm probably a better player than I was 10 years ago."
Zverev, who turns 20 next month, downed Wawrinka 4-6, 6-2, 6-1, and showed no ill effects by playing just 24 hours after winning a three-setter over John Isner that went entirely to tiebreakers.
"I played well in the second and third," Zverev said. "I turned it around a little bit. I had to be aggressive."
Zverev won 26 of the 36 points played in the final set.
"I had no more gas in the second and third sets," said Wawrinka, who smiled when a surprise birthday cake — replete with 'Stan The Man' lettering — was brought into his post-match news conference. "But at the end of the day, you have to try with what you have that day, and today was not enough."
Nadal won the only break point played in his match against Marut, and it was enough. He was an up-and-coming 17-year-old when he faced Federer at what was then called the NASDAQ-100 Open in 2004, and surprised many with a straight-set win that day.
More than a decade later, they're still rolling.
"It's a good start of the year, I think, for both of us," Nadal said. "Obviously, it's a little bit better for him, but at the same time I'm happy with the way that I am playing, happy with the way that I started the year after a tough second part of the year last year with injuries.
"So I think it's a positive for both of us that we can still (be) around here and be very competitive almost every week that we are playing."
Federer had a battle with Bautista Agut, and seemed to enjoy himself. He needed — and got — a break with Bautista Agut serving for the first set, and with Federer serving at 4-5 in the second they played about a half-dozen back-and-forth shots at the net in a tete-a-tete that ended with Federer winning the point.
He cracked a slight smile as the crowd roared. Federer gets Wednesday off, and will meet 10th-seeded Tomas Berdych on Thursday in the quarters. Berdych advanced with a 6-3, 7-5 win over Adrian Mannarino.
"You'll always take those days off," Federer said. "They are worth gold."
Nishikori will next face unseeded Fabio Fognini of Italy, who beat Donald Young 6-0, 6-4. Young's loss meant only one American man would reach the quarters — that being No. 13 Jack Sock, who beat Jared Donaldson 6-2, 6-1.
Karolina Pliskova, who has never found Miami exactly to her liking, got into the women's semifinals with a 6-3, 6-4 win over 26th-seeded Mirjana Lucic-Baroni. It's the first time Pliskova has made the semifinals at Key Biscayne.
Pliskova improved to 23-3 this year, the best record on the women's tour. She'll next face 12th-seeded Caroline Wozniacki, a 6-4, 6-3 winner over unseeded Lucie Safarova.
"I'm really enjoying my tennis this year ... winning almost every match so far," said Pliskova, who took advantage of 10 double faults by Lucic-Baroni and avenged a loss to her in the Australian Open quarterfinals.