Rafael Nadal beat American John Isner over two tie-breaks in the Western and Southern Open final and will replace Andy Murray as world number two tomorrow.
The Spaniard's 26th title at ATP Masters 1000 level, the highest tier below the grand slams, means he leapfrogs Wimbledon champion Murray ahead of this month's US Open. And Nadal also stands to be the second seed in New York even though the Scot will be defending his title.
He also equals world number one Novak Djokovic's record of five Masters 1000 titles in a season after taking a 7-6 (10/8) 7-6 (7/3) win over big-serving Isner, who fired down 11 aces to Nadal's six.
Both Murray and world number one Djokovic were eliminated in the quarter-finals in Cincinnati this week.
The first set of the final went on serve throughout. With Nadal serving at 6-5 behind, Isner opened up a 15-40 lead to set up two set points. Nadal, though, hit two successive aces to help him force a tie-break which he won 10/8 with his second set point.
There were once again no breaks in the second set and this time the tie-break was more comfortable for Nadal, who won the first two points and led all the way before taking his first match point.
Isner told atpworldtour.com: "I played extremely well all week. Thought I played well again today. Unfortunately, it just wasn't good enough.
"I'm going to hold my head up high after today's match and after this whole week. But Rafa was better than me today."
Nadal has a 53-3 win-loss record this year, including nine titles and now a career-best 15 consecutive hard-court match wins.
Nadal told the ATP website: "It means a lot. Being able to win two straight titles, two Masters 1000 on hard (courts) back to back is just amazing for me. I never did something like this in all my career.
"It was an emotional moment for so many different facts. First of all, I won a very important tournament, Masters 1000. Second thing, after all the (injury) problems that I had, it was two weeks in a row on hard playing at the highest level.
"Then the ranking is there. I was playing for a lot of points this week and I'm in a good position."
Victoria Azarenka took the women's title, coming from a set behind to beat world number one Serena Williams in a third-set tie-break for a 2-6 6-2 7-6 (8/6) victory.
Williams swept through the first set in lightning-quick time, taking both of her break points and winning 28 for 39 points in total to win 6-2.
But she trailed 4-1 in the second after a flurry of unforced errors and though she saved an incredible seven break points in the next game to avoid a third break of her serve, Azarenka held and then did break again to win the set 6-2.
The Belorusian broke for a 4-2 lead in the decider but Williams hit back straight away - and broke again to lead 5-4.
That left her serving for the match but she fell 15-40 behind after netting a forehand and was broken as Azarenka produced a superb return right to her feet.
The second seed held serve and had won eight out of the last nine points, but Williams served out to 15 to set up a tie-break.
Azarenka made the first move and opened up a 3-1 lead and restored her cushion after Williams pulled back the mini-break. From 4-2 at the change of ends, though, Azarenka fell 5-4 behind after losing successive service points.
That left Williams needing to win her two service points to take the title - but she missed a glaring opportunity on the first after opening up the court with a drop shot and then double-faulted on the second.
Azarenka sent a backhand long on championship point but set up another with a deft volley and Williams netted a forehand.
Azarenka said: "Obviously it's a big win. It was a great match. I'm really, really pleased with the way I pulled it out. It was a great battle. Nothing was given away. It was pure fight. I'm really happy."