How would you rate Roger Federer’s performance today [he beat Gilles Muller, a qualifier, 7-6, 6-4, 7-6 to earn a place in the semi-finals] – are we expecting too much to think he should dispatch a qualifier much more convincingly than that?

It is probably best not to expect too much from Roger at the moment, because then you will not be disappointed. It was another so-so performance – he got the job done without ever looking like he was in total control, which pretty much sums up his whole tournament. He may have failed to impress so far, but now he can’t get away with anything other than his very best - next up is Novak Djokovic. Opponents have fallen for Federer in the draw [he has reached the semi-finals and has yet to face anyone seeded higher than 23]. That’s all about to change – he has to hit the heights and maybe having to overcome a truly top-notch opponent is just what he needs.

Haven’t really seen much of Muller before – what’s his story?

He's a good player. He first came to our attention in the Davis Cup four or five years ago when he beat Arvind Palmer in the opening singles in Luxembourg, though Great Britain went on to win the tie. He's got some big-name scalps under his belt, he's beaten Roddick, beaten Agassi, he's a big tall guy with a big serve but had disappeared off the radar in recent times. He had been playing a Challenger event in Istanbul, flew in on Tuesday and made it through the qualifiers before going on to claim some notable victories in the main event, including one over Tommy Haas.

Fine margins in the mixed doubles, as always [Britain’s Jamie Murray and his partner Liesel Huber were beaten 7-6, 6-4 by Leander Paes and Cara Black in the final]. Had Jamie made that volley [on set point in the first set] it could have been so different. What did you think of the match?

It was unlike Wimbledon [Murray won the mixed title with Jelena Jankovic there last year] where the place was packed after the men's singles final, here it was as dead as a dodo with five-sixths of the stadium empty, there were very few people around. It's another farcical situation with this tournament, playing a grand-slam final at midday on a Thursday. If you are going to hold the competition then give it the respect it deserves. Often the mixed tends to be an afterthought, here it is a super afterthought. Having spoken to many of my colleagues here there is general dismay over the scheduling and I hope that the powers that be will take on board the criticism that has been raining down on them for the past 48 hours. But then again I have been coming here for so long that I probably know that that's not going to happen.

You’ve hardly put a foot wrong in your US Open predictions so far, so let’s put you on the spot again – Murray or Nadal, by how many, and why?

Let's keep our powder dry on that one until tomorrow, but just to add that Nadal was off playing golf today so he's incredibly relaxed. Murray was getting all his media commitments out of the way so he could have Friday to prepare properly for the monumental match to come.

Fair enough, it you won't tell us how you think young Andy is going to get on just yet, what about today's women's singles semi-finals: Elena Dementieva v Jelena Jankovic and Dinara Safina v Serena Williams?

I picked Dementieva versus Serena very early on and I don't see any need to change now. Serena came through, barely, against her sister [Venus, in the quarter-finals] and it was probably the best Williams match I have seen. Serena was a little fortunate to escape, particularly in the second set when Venus had set points. Serena is a bit of a survivor and she will have a bit too much experience for Safina, particularly on that court which she knows so well. As far as the other semi-final goes, I think Dementieva will win if she can hold it together emotionally. Jankovic hasn't played anyone who hits as many lines as Dementieva and sheer will-power alone will be enough to see the Russian through.

Neil Harman was talking to Richard Neale