Stosur the Australian lone ranger

Samantha Stosur is the only Australian left in the US Open singles after Carsten Ball lost his men's second-round match against Spaniard Albert Montanes.

Montanes smoked Ball 6-4 6-3 6-1 on Thursday in the steamiest conditions of the tournament so far.

New York is experiencing its hottest summer on record but Ball refused to blame the furnace-like temperatures at Flushing Meadows for his disappointing demise.

'It's hot for everybody. It's not unfair to any individual,' the big-serving leftie said.

'You could definitely feel it out there, there's no doubt about that, but it came down to how I executed and I didn't really do that today.

'The heat would always help me and my game style, especially against somebody like him who doesn't necessarily play such an aggressive game style as myself.' Montanes is no mug.

The 29-year-old is enjoying his best-ever ever season, he beat Roger Federer in Estoril in May and has broken into the world's top 25 for the first time.

'He played well on the big points,' Ball said.

'I had a couple of 30-alls on his serve and I was in an aggressive position and he came up with a few big shots to turn the first set around.

'Then it's always tough to bounce back, especially when you get broken first game in the second.

'That gives him a lot of confidence and, if he's up a set and a break already in the heat, that probably kept him mentally fresh. It also obviously makes me think that I'm in some trouble.

'But I feel like I didn't play that great. I could have played better but it is what it is and I tried my best.' Ball's departure leaves Australia without a men's representative in the last 32 for only the eighth time in the 42-year open era.

Lone ranger Stosur will play unseeded Italian Sara Errani for a place in the fourth round of the women's event on Friday (Saturday AEST).