By Martyn Herman
LONDON (Reuters) - Standing a set and 5-1 up in the Wimbledon final against a Spaniard playing only her second match in tennis's most famous arena, a fourth consecutive grand slam singles title looked a formality for Serena Williams on Saturday.
She duly completed the job against Garbine Muguruza 6-4 6-4 to claim the so-called 'Serena Slam' and will head to the U.S. Open bidding to become only the third woman to win the "calendar year" Grand Slam in the professional era.
But an angst-ridden finale in which Muguruza tenaciously fought back showed that, despite Williams's vast experience and vice-like grip on women's tennis, crossing the finishing line for a 21st grand slam title made her heart pound just as fast as when she made her first breakthrough at the 1999 U.S. Open.
Which, for her rivals hoping that at nearly 34 the American will become blase about collecting trophies, is bad news.
"I just learned that all the people are nervous, even Serena, in a final, because I saw it," Muguruza, the first Spaniard to contest a Wimbledon women's singles showpiece match since Arantxa Sanchez-Vicario in 1996, told reporters.
In securing her sixth Wimbledon title and first since 2012, Williams became the oldest woman to win a grand slam in the modern era, 16 years after winning her first.
It seems unlikely anyone can stop her march into the history books at Flushing Meadows where she is unbeaten since 2011.
On Saturday, however, it was the feat of holding all four majors concurrently, something she also achieved at the 2003 Australian Open, that was foremost in her thoughts.
"I honestly wouldn't have thought last year after winning the U.S. Open I would win the Serena Slam at all," said the world number one. "It's super exciting.
"I just knew I wanted to win Wimbledon this year. Of all the grand slams, it was the one I hadn't won in a while."
Muguruza, the clean-hitting 21-year-old born in the Venezuelan capital Caracas, played magnificently in the first set, leading 3-1 and 4-2 before Williams raised her game after a sluggish start to take the opener.
The enormity of the occasion and the sheer presence of Williams then seemed to hit home and the Spaniard crumbled, losing 14 out of 15 points to trail 5-1 as her vastly-experienced American opponent closed in for the kill.
Then, Williams got a bad attack of the jitters before regaining her poise in the nick of time.
"You'd be surprised, I feel vulnerable every time I step out there," she said. "It's just overcoming those feelings."
She was totally dominant until, serving at 5-1, she was broken to love. Muguruza then started swinging as she had in the early stages of the match when she had broken serve in the opening game and led 3-1.
Williams began to miss and the 20th seeded Muguruza, cheered by the Centre Court crowd, held for 3-5.
It still seemed only a hiccup for Williams as she stepped up to serve for the match for a second time.
But her anxiety was apparent when she began the game with an eighth double-fault, gesticulating to her players' box where her family and friends, including rapper Drake, watched on.
Muguruza won the next two points with backhand winners, the second one almost leaving Williams in a heap on the baseline.
Williams replied with an angry ace and screamed, "Where have you been?" to her trusty weapon. Two more booming aces earned her a match point but a tense rally ended with Muguruza punishing a mid-court ball.
At deuce a Williams onslaught was repelled and she snatched a backhand into the net and a point later the set was back on serve when the Spaniard wrong footed the top seed.
Muguruza could not sustain the recovery though and a double-fault and a net-cord calmed Williams' nerves and she converted her second match point when Muguruza hit wide, although silence briefly reigned as both players seemed unsure whether the ball had clipped a line.
"There was definitely pressure towards the end, Garbine really stepped up to the plate today," Williams added of her young opponent who shed tears when receiving a long ovation as she collected her runners-up trophy.
Swiss veteran Martina Hingis, 18 years after winning the singles, provided a fitting finale to the day when the 34-year-old partnered India's Sania Mirza to the women's doubles title.
The top seeds beat Russia's number two-seeded Ekaterina Makarova and Elena Vesnina 5-7 7-6(4) 7-5, having won the final two games under the Centre Court roof before a noisy crowd.
Earlier, Dutch/Romanian duo Jean-Julien Rojer and Horia Tecau later won the men's doubles beating Andy Murray's brother Jamie and his Australian partner John Peers 7-6(5) 6-4 6-4.
(Reporting by Martyn Herman; Editing by Ken Ferris)