Matches to watch, day 9

Some of the possible tight contests from yesterday turned out to be rather one-sided, in the end. Federer and the Williams sisters all won, with only Venus having even a hiccup. Wozniacki lost injured, and Zvonareva had a patented meltdown. But that's not to say there weren't good matches!

Davydenko-Verdasco was hard fought, with some great shots and good rallies, but the only reason it was tough was due to a couple of mentally weak moments from both players. Verdasco nearly gave away an entire set in double-faults, while Davydenko hit fewer winners in 52 games yesterday than he did in 22 games in his first round match. Still, a good contest, for the honor of facing Federer.

Tsonga-Almagro was also a tough match, with a bit more mental toughness being shown by both players. Tsonga played (and won) his first five-setter, while Almagro stumbled just short of his first quarterfinal at a hard court major. Both players are tons of fun to watch, move well, and hit stupendous shots. Almagro should have had a better career by this point, considering his talent. He'll be back.

Looking ahead to the first night of the quarterfinals, the tournament has really entered crunchtime at this point. Really, every one of these is a match to watch.

Andy Murray v. Rafael Nadal - You could reasonably expect to see this match in a final, and here we are in the quarters. Murray has shown better form heading into this match (his play against Isner was imperious) but Nadal has the edge in their head-to-head, even on hardcourts. They met here for the first time three years ago and had a five-set epic, which Nadal ended up winning 6-1 in the fifth. At that point, it was all about fitness. This time, I think Murray is much stronger and healthier, so it will down to mental strength, and whether or not Nadal can get back into his very best form.

Andy Roddick v. Marin Cilic - Roddick must have been happy to see Del Potro out of the tourney, but the opponent he ended up with in the quarters is basically just Del Potro lite. Cilic has a similar game, with just less overwhelming power behind the forehand and fewer big-stage results. But he's just as eager, if not more so, by his lingering outside of the top ten. Roddick will have his work cut out for him, and he's had trouble with up-and-comers at the big stage, in the last few years.

Justine Henin v. Nadia Petrova - Even though she's only played about ten matches since her comeback started, Justine Henin has already beaten Petrova, in two tight sets in the first round at Brisbane. Even though Nadia has won two spectacular matches in the last two rounds, it's tough to see how her game has changed enough in the past three weeks to change the outcome of this match. But I keep saying Justine has got to be getting worn down by the grind of a Grand Slam, after so long away. I feel like I have to say it again, even if it's never going to actually be an issue.

Jie Zheng v. Maria Kirilenko - Two surprise quarterfinalists! Who knows which one of these two is going to make it through, but the odds are great that whichever one it is will then lose to either Henin or Petrova.