NEW YORK — On the very first point of the match, Serena Williams hit a backhand so hard that her earring flew off.

Turns out she was just getting warmed up.

Williams kept pounding away, her shots and shouts getting louder with every stroke. And when she finished off Jelena Jankovic 6-4, 7-5 Sunday night for the U.S. Open championship and a ninth Grand Slam title, Williams really went wild.

She flung her racket high into the sky, hollering and hopping in a celebration that even she thought might’ve been over the top.

“I’m sorry I got so excited,” she told Jankovic when they met at the net.

The fourth-seeded Williams beat sister Venus in the quarterfinals and barreled through this tournament without losing a set. This win did more than earn Serena her third silver trophy at Flushing Meadows — it assured she will return to No. 1 in the rankings for the first time since August 2003, the longest gap at the top for a woman.

Pretty good for someone whose ranking once plummeted to No. 139.

“It’s been so long,” she said.

Given the way Roger Federer has played lately, it seems like it’s been a while since he’s been on top, too.

Federer will try for his first Grand Slam win this season — and fifth straight U.S. Open championship — today against Andy Murray, who beat No. 1 Rafael Nadal 6-2, 7-6 (5), 4-6, 6-4 Sunday in the completion of a match interrupted by rain.

The second-seeded Federer is aiming for his 13th major title, which would put him one shy of Pete Sampras’ record. Murray, hoping to become the first British man to win a major tennis title since Fred Perry at the 1936 U.S. Open, is making his first appearance in a Grand Slam final.

“He’s got loads of experience in these situations, and it’s something new for me,” Murray said. “I know I’m going to have to play great to have a chance of winning, but I’ve played well the last couple of weeks.”

Plus this: Murray is 2-1 lifetime against Federer.

Williams calmed down in time for the on-court trophy presentation, and smiled when she received the winner’s check for $1.5 million. Still full of personality, Jankovic wondered aloud, “How much did I get?”

Jankovic earned $750,000 for her first showing in a Grand Slam final.

This was the 13th straight time that the women’s championship at the U.S. Open was decided in straight sets. The second-seeded Jankovic certainly had her chances — up 5-3 in the second set, she led 40-0 with Williams serving.

“I felt I had her. I had her, because she was really tired at the end of the second set,” Jankovic said. “Who knows what would have happened if I had got into a third set? I probably would have had the upper hand. But who knows?”

Jankovic won over fans with more than her determined play and her penchant for doing the splits to reach shots. She’s a crowd favorite, often talking to people in the stands and frequently watching herself on the giant video boards high above Arthur Ashe Stadium.

At one point, she saw herself on the screen and promptly fixed her hair.

“They should turn it off, because I keep looking,” she said. “You see your big face up there and you can’t help but look up.”

Venus Williams got ample air time, too. Sitting in the guest box, she cheered on the sister she teamed up with to win the Olympics doubles title.

Serena Williams won her first Grand Slam championship since the 2007 Australian Open, and took over the No. 1 ranking Jankovic held last month for exactly one week.

“I feel so young and I feel so energized,” Williams said. “Sometimes, I’d wake up at 6 in the morning to go practice and it was too dark.”

Williams and Jankovic originally were scheduled to play Saturday night, but rain from Tropical Storm Hanna delayed their match.

The sixth-seeded Murray beat Nadal in the first two sets and was down 3-2 in the third when they were postponed Saturday afternoon.

Nadal came out strong when they resumed, winning the third set and then going ahead 3-1. But Murray regained his momentum and nerve, and had Nadal on the run by the end.

“He beat me because he was better than me,” Nadal said. “When he’s playing aggressive, he can beat everybody.”

Nadal won at Wimbledon, the French Open and the Olympics, but seemed drained by his 84th match of the year. He’d won 19 straight matches in majors, though he’d never reached the final at Flushing Meadows.

Murray beat Nadal for the first time in six career matches. Even when the 21-year-old Scotsman slipped toward the danger zone, he felt confident.

“I go on the court now without feeling like I have anything to worry about, because I’ve worked hard and practiced hard and given myself the best opportunity to play well,” he said. “All I’ve got to do is play tennis, which is one of the few things that I’m good at.”