Roger Federer made a smooth start to his Cincinnati Masters title bid by beating Frenchman Julien Benneteau 6-3 6-3 but Rafael Nadal was forced to retire and Novak Djokovic lost on Wednesday.
An early break put Federer, looking for his 50th career title, on his way and after taking the first set, he broke in the seventh and ninth games of the second to clinch victory.
The Swiss top seed and world number one will next play Marcos Baghdatis of Cyprus, who beat Argentine Juan Ignacio Chela 6-7, 6-4, 6-2, in the third round.
"It gives you a fright when you see some people retiring and others, like Djokovic, who had the tournament of his life last week, losing quite comfortably," Federer said in a courtside interview.
"It puts extra pressure on you so I'm happy I am the one to survive."
World number two Nadal quit when trailing Argentine Juan Monaco 7-6, 4-1 in their second-round match, citing cramp in his left forearm and dizziness.
"I have some cramping," Nadal told reporters.
"I wasn't grasping the racket very well and I wasn't feeling very well when I went to the court. I couldn't play more than three balls on every point. I didn't have power in the legs."
World number 25 Monaco now plays American Sam Querrey, who upset 13th seed Mikhail Youzhny of Russia 5-7 6-3 6-4.
GOING DOWN
Serb Djokovic, who beat Andy Roddick, Nadal and Federer to win the Montreal Masters last weekend, was brought back to earth with a bump by former world number one Moya, going down 6-4, 6-1.
Moya broke once to win the first set. World number three Djokovic had a break point in the opening game of the second set but Moya saved it and broke three times to clinch victory and set up a clash with Argentina's Juan Martin Del Potro.
"I felt a bit tired and didn't have enough time to prepare for this tournament," Djokovic said.
"I arrived two nights ago, but I played doubles yesterday. I played 10 days there then I had this travelling. Basically I didn't have a day off. It's not easy."
"I'm still getting into professional tennis, playing every tournament, basically to the end of the last two, three days," he said.
Another Spanish former world number one, Juan Carlos Ferrero, upset sixth seed Fernando Gonzalez 6-2 7-6 to reach the third round.
The Spaniard, runner-up last year, cruised through the first set and won the second-set tiebreak 9-7, clinching victory on his sixth match point to set up a meeting with American ninth seed James Blake, who beat German Nicolas Kiefer 6-4, 6-4.
Croatian 11th seed Ivan Ljubicic suffered a surprise 6-4, 6-4 defeat by Spaniard Nicolas Almagro but there were wins for fifth seed Nikolay Davydenko and 10th seed Tomas Berdych.
Another former world number one, Lleyton Hewitt, went through when eighth seed Richard Gasquet retired at 6-1 3-2 down because of blisters.
Hewitt will next face Austrian Juergen Melzer, who saved two match points before beating Croatian Mario Ancic 6-3, 2-6, 7-6.
