Roger Federer believes that criticism from tournament organisers of a spate of pullouts at the year-ending Masters Cup was fully justified.
The world number one refused to condemn Chinese organisers for calling into question Andre Agassi's reasons for quitting the $4.45 million (2.6 million pound) tournament earlier this week.
"I think criticism is allowed at this point," said Federer after making it two wins out of two in Shanghai on Tuesday.
"They signed a three-year deal. I understand the big disappointment from the government, from the tournament, from the fans."
Agassi pulled out on Monday citing an ankle injury after hobbling to a 6-4, 6-2 defeat by Russia's Nikolay Davydenko in his first match.
The American's withdrawal came after Spain's French Open champion Rafael Nadal pulled out through injury. Andy Roddick, Marat Safin and Lleyton Hewitt were all Shanghai no-shows.
Organisers were scornful of Agassi's decision to withdraw even though the eight-times Grand Slam winner arrived in China with an ankle injury.
But Federer sought to heal any potential rift by praising Agassi for trying to play on his sore ankle.
"I don't know how bad it really was...but I think it's still great that he shows up and tried," said Federer. "Maybe the other guys could have tried too.
"I don't know. I don't think so because they know their bodies."
Federer himself was on crutches just three weeks ago after hurting his ankle in practice but has beaten David Nalbandian and Ivan Ljubicic to close in on a third straight Masters Cup title.
"I came here not knowing if I could play and I went through the therapy just to really show the people how much this event really means to me," said the Wimbledon and U.S. Open champion.
"Sort of arrived basically on one leg. Now that I can play it's fantastic. It should also show a message how important this tournament is to tennis. For me this equals a Grand Slam."
