Originally Posted by abmk
well, IMO, the roof being closed did play a part in those stats.
at wimbledon :
I think federer served exceptionally brilliantly in the semis, but he did return better in the finals ..
murray in the finals also returned quite a bit better than djoker did in the semis ...
the matches were closer in quality than the respective AMs seem to suggest ...
differences being the roof and the better quality of returning resulting in more rallies and as a result more UEs in the final
I will admit, I am a bit surprised that they have federer at only 10 UEs in the semi. I thought he made more than that ...
I agree with a lot of this, though I would question whether the lower AM's in the final were due to better returning.
This gets to the issue we've been debating in recent days in this thread, about whether it's possible for two players to lift their play, from one match to the next, but for their AM's to stay the same or even to go lower.
I doubt that better returning can result in lower AM's. Let's say I make 20 unforced errors on the return, in one match. I cut that down to 10 in the rematch. The quality of play has gone up, and my AM will be higher, because I've cut down on my UEs.
You said that the better returning produced a greater number of rallies, and that long rallies tend to end in UEs. I agree that long rallies often end in UEs. But not all of them. Some of those points -- in fact, a decent number, even among insanely good defenders like Nadal and Djokovic -- will end in winners, or in forcing shots.
Let's do the math. On the return, I reduced my UE's by 10. Yesterday on those 10 points I didn't put the ball back in play; today I made rallies out of those 10 points. Let's say I make UE's on 6 of those rallies. I still have an overall improvement of 4 UE's.
If I reduced my return UE's by 10, and ALL TEN
rallies ended in UE's, then my AM would stay the same. But the chances of that happening are small. If even one of those points ends with me making a winner or a forcing shot, then I've come out ahead overall, and my AM will rise from the previous day.
As for the real matches at Wimbledon, I'm not sure that the returning was better in the final than in the semi.
Unfortunately I only saw the middle of Fed-Djokovic. (I saw all of the final). I did notice Djokovic having trouble with Federer's serve, and I wondered whether Djokovic was just having an off day, or whether his trouble was due to Federer's serving. I really thought Djokovic looked handcuffed by Federer's serve, for the most part.
Wimbledon.org had Djok making only 8 UE on the return, which is pretty good returning in a four-set match. They had Federer making only 5 UE on the return -- so Federer really could not have returned much better, if at all, in the final.
Fed/Djok had the roof closed throughout. Federer's serve traveled faster by a few mph whenever they closed the roof. In the final, when they closed the roof one of the announcers said that his average 1st serve went up by 5 mph.
But the Fed/Djok semi was played entirely under the roof, and if you look at the Wimbledon boxscores Federer did have more mph on his serves in the semifinal, as compared to the final. His average 1st serve was 2 mph higher in the semis. His average 2nd serve was 4 mph higher, which is a significant margin -- and that partly explains how Federer managed to win 72% of his 2nd serve points in that match. That's just phenomenal; I fully agree with you that he served extremely well against Djok.
But I think that means that Djokovic looked like he was returning worse than Murray, because Djokovic had to deal with better serves.
The same seems to be true on the other side of the coin. Did Federer improve his returns, going from the semis to the finals? Or did his returning just look worse against Djokovic, because Novak was serving better than Andy?
I think Novak was serving better. Perhaps the indoor conditions helped the mph on his serve. Murray barely had a faster 1st serve, on average, than Djokovic (121 mph vs 120 mph). But on second serve Djokovic was clearly superior: 95 mph vs 88 mph.
So Federer's returning may have looked better in the final because he had more of a puffball to deal with, on second serves.
7 mph is a significant difference. And yet Federer, dealing with these faster second serves from Djokovic, made only 5 ue's errors on the return.
Federer cannot have cut that number down by much, if at all, in the final.
So I think if the AM's are lower in the final than in the semifinal, we may need to look for another cause.
The mph figures, and the return UE's counts, actually suggest that the semifinal had better serving and returning than the final did.
And if so, that's reflected in the AM's.