LONDON — When her opponent’s final shot sailed out, Serena Williams wasn’t sure whether the match was over.
It took a few seconds before the realization sunk in — not only had she won her sixth Wimbledon singles title, her bid for another “Serena Slam” was complete.
Williams overcame a slow start, eight double-faults and a nervy finish to dispatch Garbine Muguruza 6-4, 6-4 on Saturday for her fourth Grand Slam championship in a row and 21st major title overall.
The win means Williams holds all four Grand Slam titles at once — completing the second “Serena Slam” of her career. What’s more, she secured the third leg of a calendar-year Grand Slam and, if she wins the U.S. Open, will become the first player to sweep all four majors in the same season since Steffi Graf in 1988.
“I can’t believe I’m standing here at another Grand Slam,” Williams said in an on-court interview after the match. “I’m having so much fun out here. I just never dreamt I would be out here still and let alone winning.”
Williams, who won her 28th straight Grand Slam match, is now just one major title behind Graf on the Open era list and two behind all-time leader Margaret Court.
At 33, Williams also is the oldest woman to win a Grand Slam title in the Open era. She has now won eight major championships in her 30s, including her first Wimbledon title since 2012.
“It feels so good,” Williams said after accepting the winner’s trophy — the Venus Rosewater Dish — at Centre Court from the Duke of Kent. “It’s been a little while, and you really appreciate holding it.”
Williams was broken in the opening game by Muguruza, a hard-hitting 21-year-old Spaniard who was playing in her first Grand Slam final, and fell behind 4-2. But Williams began playing more aggressively and ran off five consecutive games to take the set and go up 1-0 in the second.
Williams pulled out to a 5-1 lead but seemed to get tight and was broken twice serving for the match.
Muguruza saved a match point and converted on her fifth break point to draw within 5-4. But Williams then broke at love in the next game to close out the match.
Neither player seemed to realize the match was over, and there was an awkward delay before Williams covered her face with both hands, then smiled and raised her arms in the air.
Muguruza, the first Spanish woman to reach a Grand Slam final in 15 years, was bidding to become the first to win Wimbledon since Conchita Martinez in 1994.
“I learned that she’s also nervous, even though she played I don’t know how many finals,” Muguruza said. “And she finds the way, being so nervous, to serve, to hit winners. She’s the world No. 1. That’s what I saw today.”