Poor guy had to be helped in the tunnel and refused a wheelchair.
He was also unable to do his post-match interview.
I know - and exhaustion and injury aren't a good combination either. I agree with Robbie that fitness is the key here, although as a top 20 player, I wouldn't have expected Simon to be that exhausted after this match, especially as it wasn't played in extreme temperatures. He needs to have a word with his fitness trainer, I think. Also Simon has been without a coach since September last year, so maybe this played a part here too. I wouldn't though rule out Simon attempting to play Andy - Gallic pride, and all that - but I really would have preferred Monfils as his opponent. Their H2H is 3-2 Andy, and they last met in 2010 - in Toronto, where Andy won comfortably, and again in Paris, where the situation was reversed - although Murray fans may wish to draw a veil over that one.
Andy doesn't need a walkover in any sense of the word.
I think you can look at it two ways - either from the point of view of conserving energy, or the fact that most players, including Andy, would prefer to keep the momentum going, and he's going to have a long gap if he doesn't play on Monday. OK, so he can always practise, but there's big difference between that and playing a match, and I'm not amongst those who are taking Andy reaching the SF for granted.