German veteran Tommy Haas ousted Nicolas Almagro in the first round of the Shanghai Masters on Monday, dealing a huge blow to the Spaniard's hopes of qualifying for the ATP World Tour Finals.
The former world number two withstood a barrage of 18 aces and saved seven of eight break points against the ninth seed, battling back from losing the first set to win 4-6, 7-6 (7/4), 6-2.
The 27-year-old Almagro, bidding to qualify for the end-of-season showpiece for the first time, started the week in 10th place in the Race to London but could not compete with the quality of Haas's game in the decider.
Haas, 34, who earlier this year won his 13th Tour title by beating Roger Federer in Halle, Germany, has risen from outside the top 200 at the start of 2012 to his current ranking of 21.
Elsewhere on day two of the Shanghai Masters Richard Gasquet, also chasing one of the remaining four slots in London, rediscovered the winning formula after last week's shock defeat in Beijing.
Gasquet crashed to a humiliating loss at the China Open to Chinese wildcard Zhang Ze, who was ranked 151 places below him, just days after the Frenchman won the Thailand Open by beating compatriot Gilles Simon.
But the 26-year-old, seeded 11th in Shanghai, made sure there was no repeat on the second day of action in Shanghai, winning four out of five break points to dispatch American journeyman Brian Baker 6-2, 6-3.
Tenth seed Marin Cilic, who stands 6 feet 6 inches (198 cm) tall, joined him in the second round with a 7-5, 6-3 victory over Lukasz Kubot, hitting eight aces and breaking his Polish opponent four times.
It was the first main draw match win in four attempts at the Shanghai Masters for the 24-year-old Croat, who fell in the first round in 2009-2011.
Earlier, Sam Querrey of the United States fired 11 aces in a 6-3, 6-1 victory over Chinese wildcard Zhe Li.
"I feel like I'm playing better now than a year and a half ago when I was ranked number 17," said Querrey, now ranked 26th.
"I'm more confident," he added. "Felt good out there today. It was fun to play in that stadium. I thought I served great. I thought I returned well and I took advantage of the break points. That was the key."
Bulgaria's Grigor Dimitrov set up a clash with Novak Djokovic by beating Pablo Andujar of Spain 7-5, 6-3. But he faces a daunting task against the second seed, fresh from victory at the China Open and aiming to displace Federer at the top of the rankings.
The number one ranking is on the line at the Shanghai Masters.
Federer can guarantee he remains as the top-ranked player by reaching the quarter-finals but anything less and Djokovic would overtake the Swiss by winning the Shanghai crown.
Frenchman Benoit Paire defeated German qualifier Philipp Petzschner 7-6 (7/2), 6-4 to set up a clash with compatriot Jo-Wilfried Tsonga, the fifth seed, and there were also wins for Spain's Tommy Robredo and Kevin Anderson of South Africa.