Newly recrowned world number one Rafael Nadal can smash the record for Masters titles claimed in a year in Shanghai this week, as his great rival Roger Federer fights to save his season.
Nadal has enjoyed one of the best spells of his career after he came back from a career-threatening injury to win two major titles, but he is still seeking further accolades.
After replacing Novak Djokovic at the top of the new ATP rankings - despite his loss to the Serb in Sunday's China Open final - Nadal can now become the first man to win six Masters trophies in the same season.
And the remorseless Majorcan, storming into Shanghai as Typhoon Fitow also hits eastern China, is also targeting the coveted title of year-end world number one.
"If I am able to be number one at the end of the season, then that's an important achievement because I will be the best of the year," he said. "That's something that really motivates me."
Since returning in February after seven months out with a left knee injury, the Spaniard has won 10 titles, including the French Open and US Open.
Until Sunday's loss to Djokovic, he had been unbeaten since his early exit at Wimbledon, where he was a shock first-round loser to Belgium's Steve Darcis.
"This is a great year, one of the best years of my career without any doubt," said Nadal, who is now just four grand slams shy of Federer's record of 17.
"It sure is special to be back to the top position of the rankings after more than a half-year without playing tennis."
Second seed Nadal equalled Djokovic's record of five Masters titles in a season by winning at Cincinnati in August. He has twice been year-end world number one, in 2008 and 2010.
Federer, by contrast, has endured a wretched season by his standards and risks missing out on the season-ending World Tour Finals, held in London, for the first time since 2001.
He has won the event, which features the season's top eight players, a record six times. But Federer has won one title this year and failed to reach any of the grand slam finals.
With the season entering its final few weeks, the Swiss still has work to do to reach the end-of-season showpiece. But Federer has a tough task in Shanghai, slated to meet defending champion and top seed Djokovic in the quarter-finals.