PARIS — Celebrating the best season of his career, Andy Murray cemented his rise to No. 1 by beating John Isner 6-3, 6-7 (4), 6-4 Sunday to win the Paris Masters for the first time.

It was his eighth title this year, his 14th in Masters overall. It also ended Isner's bid for a first Masters title.

"I felt really nervous before the match," Murray said, despite having beaten the big-serving American in all seven of their previous career meetings.

Murray will officially replace Novak Djokovic at the top of the rankings when they are published on Monday.

"It might only be for one week. So, I might as well try and enjoy it," Murray said. "Because I could lose it at the (ATP) Tour Finals and never be there again."

The 29-year-old Murray is still getting accustomed to his newfound status.

"I don't really know if it's sunk in or not," said Murray, who is a three-time Grand Slam winner and a double Olympic champion. "It feels different (to) when I had won a Grand Slam or (the) Olympics."

Especially in the number of congratulatory messages.

"More than I've had after any match I have played in my life," Murray said. "It's very nice, because you have won the respect of the players."

Murray recently beat Isner 6-1, 6-3 in the quarterfinals of the Erste Bank Open in Vienna, but this was thoroughly contested.

"We played last week and the difference was huge," Murray said.

Using 18 aces and hitting plenty of inside-out winners on his massive forehand, Isner generated considerable pressure.

But he also wasted six break points overall.

In the second set, he was 4-3 ahead and 40-0 up on Murray's serve, but failed to punish the Briton — last year's runner-up to Djokovic.

But in a rare dip, Murray double-faulted during the tiebreaker and Isner profited to take the set.

Isner saved break points on his first two service games of the third set, hanging on as Murray restored his superiority.

Then, serving to stay in the match, the 2.08-meter (6-foot-10-inch) American double-faulted to trail 0-30. He won a tough first point and then hit yet another ace to make it 30-30.

Isner sank a difficult volley into the net, giving Murray a first match point. With Isner on second serve, Murray dominated a brief rally, pinging a pass down the line that Isner patted into the net with the ball close to his body.

It was a hard-fought victory and Isner stood with his head down at the net, waiting to congratulate Murray.

Murray has won four consecutive tournaments, taking his career tally to 43.

Next up is the season-ending ATP finals in London, beginning next Sunday.

Murray will cross the English Channel to try and take the title there, having secured his top ranking here.

"This has been an incredible journey to get to the top of the rankings," said Murray, whose brother Jamie is among the world's best doubles players.

"There haven't been many tennis players from Scotland over the years, and a lot of what we have done is big credit to our parents," Murray said. "Our mum was a tennis coach. She helped us learn the game really and helped us enjoy the game at a young age."

The 31-year-old Isner, playing in the third Masters final of his career, ends the year without a title.

He lost his other final this season to Australian Nick Kyrgios at Atlanta, Georgia, in August.

Some small consolation is that he finishes the year with the most aces at 1,159 — the fourth time he has achieved this.

Murray broke Isner twice, the first time to move 4-2 up in the first set.

Isner fought back, a booming forehand winner giving him two break points in the seventh game.

Murray saved the first one with a lob — impressive against such a tall player — and volley. He rescued the second by forcing an unforced error.

Serving for the first set, Murray won the first point with an extraordinary backhand retrieve from a speedy Isner forehand that he somehow turned into a cross-court winner.

"That was pretty spectacular from him," Isner said. "He always clamps down on me when I have a bit of an opening."

In the second set, Isner got a deserved ovation in the eighth game when he won a 20-stroke rally.

Showing nimble footwork that belied his size, he traded shots with Murray, winning the point with a superb drop shot and then a forehand winner from Murray's retrieve.

Isner was playing his best tennis of the match and had Murray 0-40 down.

Murray recovered but gave Isner another chance at deuce.

He missed that chance, too.