The anatomy of Serena Williams' 28-0 streak

LONDON -- Even 21-time Grand Slam champions have bad days.

In May 2014 at Roland Garros, Serena Williams wasn't quite her imperial self and lost to 20-year-old Garbine Muguruza in the second round. A month later, she fell in the third round at Wimbledon to Alize Cornet. Since then, over the course of 379 days, Williams hasn't lost a Grand Slam singles match. That's four majors in a row and 28 consecutive match wins, including Saturday's 6-4, 6-4 victory over a spirited Muguruza.

And when it was over, after a curious pause, Serena walked slowly to the net and received a warm hug from Muguruza. She covered her face with her hands and looked slowly around at the applauding Centre Court fans, savoring her sixth Wimbledon title.

"It feels so good," she told the crowd while holding the trophy, which, oddly enough, bears the first name of her older sister (the Venus Rosewater Dish). "It's been a little while. I didn't even know it was over, she was fighting so hard."

And then she looked at Muguruza, tears still wet on her cheeks.

"Congrats," Serena said. "Don't be sad; you'll be holding this trophy very, very soon."

Said Muguruza: "She's still showing us that she's world No. 1."

From the hard courts of New York and Melbourne, to the red clay of Paris and now the grass at the All England Club, Serena has been perfect against opponents from 15 different countries -- including 10 from Russia and its former territories and six fellow Americans.

Williams is now in a commanding position to do something that hasn't been done in 27 years: win a calendar-year Slam. If Serena runs the table at the US Open, she will equal Steffi Graf's 4-for-4 in 1988. That would also, appropriately, match the German's total of 22 Grand Slam singles titles.

Would anyone bet against her?

"No," said seven-time Grand Slam champion John McEnroe, "not at all. I'd bet with her."

That she is doing this at the advanced age of 33 is almost taken for granted, but it shouldn't be. Serena, who turns 34 at the end of September, became the oldest woman to win a Grand Slam in the Open era. She's 26 days older than Martina Navratilova when she won Wimbledon in 1990. Think about it this way: The other time Serena won four consecutive majors was more than a dozen years ago.

For further context, consider that Serena has won more Grand Slams in the past year than all the WTA's other active players, outside of sister Venus and Maria Sharapova, have won in their careers. And her 21st Grand Slam singles title gives her just as many as all of the other active WTA players combined.

Surely, Williams has had her share of bad days during the streak, but she has always managed to rally. Analyzing the 28 matches reveals:

• Nine three-set matches, seven of which began with a dropped set. The average score of the third set in those matches: 6-2.

• A total of 56 sets won versus nine lost.

• Fifteen seeded opponents, but only three seeded in the top 10.

The French Open was her most difficult draw to navigate. Four times she lost the first set, but came back to defeat Anna-Lena Friedsam in the second round, Victoria Azarenka in the third, Sloane Stephens in the fourth and Timea Bacsinszky in the semifinals. Williams lost a second-set tiebreaker to Lucie Safarova in the finals but clinched her third Roland Garros title with a 6-2 third set.

Wimbledon was problematic at times, too.

After routine matches in the first two rounds, Serena ran into Britain's Heather Watson. Backed by a boisterous partisan crowd, Watson won the second set, and ultimately, five straight games to take a 3-0, double-break lead in the third. It was undoubtedly the toughest spot Serena had found herself in during the streak. Naturally, she rallied. She needed a six-deuce game that took nearly 10 minutes to break Watson and start a four-game run of her own.

In the fourth round, she had to play an emotionally charged match against Venus and won 6-4, 6-3.

The quarters was a test, too, with Azarenka again taking Serena to the maximum three sets. And then it was Sharapova, the other two-time opponent in this run, who fell 6-2, 6-4 in the semifinals.

Against Muguruza, who previously never advanced past the second round at Wimbledon, Serena wobbled woefully in the very first game. She entered the match averaging 2.2 double faults per outing but stroked three in that first eight-minute frame. Muguruza finally seized her fourth break opportunity and held the lead until the eighth game.

That was when Serena, dialed in on her serve, forced her third and fourth break points. Muguruza saved the first with a 99-mph ace, but on the second opportunity, Serena framed a ball, which soared skyward but dropped in. When Muguruza sprayed her forehand wide, Williams was back even at 4-all.

In the next game, she crushed a massive overhead that nearly reached the Royal Box. Serena's guttural scream announced that she was taking this seriously.

Williams is now a remarkable 20-4 in major finals, winning her last eight since her 2011 US Open loss to Samantha Stosur.

Serena had never won the first three majors of a season until Saturday. And so let the hype begin to grow. The buildup to the US Open should be fun.

"I can't believe I'm standing here with another Serena Slam," she said, sounding genuinely amazed. "There was definitely a little pressure, especially toward the end. I thought, 'OK and stay out here and do the best you can.'

"I'm having so much fun. I never dreamed I'd still be out here."