WIMBLEDON, England ? Serena Williams sat in her courtside chair, jacket over her legs and towel over her shoulders, trying to stay warm during a 10-minute medical timeout early in the final set of the Wimbledon final.

Her opponent and sister, Venus, was in the locker room getting treatment for the abdominal strain that made her double over or grimace after shots.

Of all the things that could have run through Serena’s head — What is taking so long? Will she quit? How’s my big sis doing? — here’s what she thought: “I want to make sure I hold serve here.”

Tough as it might be to stay relentless against a hurt sibling, Serena focused and beat Venus, 4-6, 6-4, 6-2, Saturday for her second straight Wimbledon title. It’s her fifth championship in the past six Grand Slams, each capped by a victory over Venus.

“I have to look at the big picture. Twenty years from now, I don’t want to look back and say, ‘You know what? I really should have fought harder,”‘ top-ranked Serena said. “It was a little more difficult, seeing as it was Venus that’s injured. I just had to tell myself to look at the ball and nothing else.”

Venus started the match — her fourth straight Wimbledon final, including wins in 2000-01 and last year’s loss to Serena — with her midsection and upper left leg taped.

She got more wrapping in the timeout after being broken to open the third set, when she double-faulted twice, put a forehand in the net and generally looked miserable.

“I couldn’t run too fast, I couldn’t stretch out too much,” she said. “I was hitting serves in the net because it’s harder to reach up.”

Her serve speeds were down around 85 mph by then, 20-to-30 mph slower than usual, and after hitting them she would wince.

Serena Williams displays the winners trophy to the crowd after defeating her sister, Venus, 4-6, 6-4, 6-2. Serena Williams claimed her second straight Wimbledon title Saturday.

But she was determined to play. This was, after all, a Wimbledon final and — perhaps more significantly — she was facing her sister. The family drew boos and jeers at a 2001 tournament in California after an injured Venus withdrew right before a semifinal against Serena.

“Everyone’s quite familiar with the history. I had to at least show up and go out on the court,” Venus said. “Serena and I have taken a lot of slack, so I felt I had to take one for the team.”

Actually, Venus might not even have been a finalist at all if not for Serena. When Venus aggravated the two-month-old stomach muscle strain during her semifinal against Kim Clijsters, it was Serena’s encouragement during a rain delay that kept her going.

Venus skipped practice Friday, and cut short a session two hours before the final, limping away after 10 minutes with a left groin twinge.

“I think she was very courageous to go out there and play,” said trainer Karen Davis, who treated Venus and predicted she’ll be out two-to-four weeks.

Two minutes before the scheduled 2 p.m. start, All England Club chief executive Chris Gorringe emerged on court with a microphone and intoned, “Ladies and gentlemen, may I have your attention, please.” The crowd of 13,810 suddenly quieted, perhaps wondering if a withdrawal announcement was coming. Instead, Gorringe merely noted that a representative of a charity would handle the prematch coin toss.

And then the players came out, Venus several paces behind, walking with a slight hitch.

She didn’t have problems early, though, winning the first game with three service winners up to 110 mph. She broke at love with a passing shot and held to 3-0 thanks to two forehand errors by Serena, capping an 11-point Venus run.

“It tugged at my heartstrings watching Venus out there,” said their mother, Oracene Price. “I didn’t want her out there in the first place, but that’s her choice. That’s what probably made it difficult for Serena at the beginning.”

Venus then had four break points to take a 4-0 lead, but erased two with backhand errors. Serena saved another with a 107 mph ace, and it was on the fourth that the fiery on-court persona she displays against everyone else first showed.

It was a spectacular 10-stroke point ending with a passing shot by Serena. She turned her back to Venus, pumped a fist, curled her body and yelled, “Come on!” Serena won the next two points for 3-1.

The next few games were marked by the powerful hitting and relentless running that elevated the sisters to the top, with strokes accompanied by shrieks.

But serving down 5-4, Serena played a poor game, as though she was easing up a bit. She fell behind love-40 with a double-fault, smacked a backhand winner to save one break point, then flubbed a 16-stroke exchange with an awkward shot that sailed wide.

Serena finished with 30 unforced errors to Venus’ 25, and the second set opened with three consecutive service breaks and the sort of sloppiness often seen in the Sister Slam finals.

Serena gained control in the second set by breaking at love to 4-1 with Venus missing two backhands and two forehands, the last sailing 5 feet long.

The final set was similar, Venus’ errors mounting as she looked more uncomfortable, slapping her left thigh while awaiting serves. When her eighth double-fault made it 5-2, she slumped over, leaning on her racket as though it were a cane.

“She’s tougher than I ever thought she was,” said Serena, 38-3 with four titles this season. She’s also 40-1 in the past six Slams, a semifinal loss at the French Open the only glitch. Venus’ last major title was the 2001 U.S. Open.

When Saturday’s match ended, the sisters hugged, and Venus stepped aside, allowing Serena to soak in the applause. Then Serena plopped down in the changeover seat next to Venus. They chatted, smiling, until Venus flagged down a club official and handed him a camera to capture the moment.

“I can’t feel sorry for myself. I know my sisters feel sorry for me, including Serena,” Venus said, and then she thought of a truly silver lining.

Speaking of the winner’s trophy, a sterling silver plate on which champions’ names are engraved, Venus noted with a smile: “One day someone is going to see ‘Williams’ and think it was me.”