'Tommy and I both played good tennis at the start, but I was able to get a break in the first set.

'In the second he gave me two break points and I took them.'

But it was not all one-way traffic for the number 11 who stands 27-7 on the season. Serving for victory leading a set and 5-2, Gonzalez lost serve to give Haas some breathing space.

After the 31-year-old German held, Gonzalez finally put the victory away a game later on his second match point as he smashed home the win in just under 90 minutes.

Del Potro was glad to have a free afternoon after the pullout of Soderling, elongating his practice to an hour and planning to relax for the rest of the day.

'I found about the pullout during my warm-up so I just extended the session,' said the world number six South American. 'I need time anyway to rest for my next match.

'The courts are playing a lot faster this year and we players can all feel the difference.'

French Open finalist Soderling said he has been feeling his elbow for several weeks. 'I've just over-played,' said the man who knocked Nadal out of that major on May 31 in the fourth round and lost the final to Roger Federer.

'I took a week off after Hamburg (July) but it is still bothering me, I hope to be ready for the US Open.'