KEY POINTS:
The top four seeds survived a day of marathon three-setters in sweltering conditions at the Auckland men's Open yesterday to set up a tantalising quarter-finals programme today.
The first seven of eight second-round matches all went to three sets, with top seed Juan Martin Del Potro, second seed David Ferrer, third seed Robin Soderling and fourth seed Nicolas Almagro all needing three sets to progress.
Del Potro, Ferrer and Almagro were all forced to fight back from a set down, while Soderling looked to be cruising against American Bobby Reynolds but dropped the second set to take what was supposed to be a day match well into the evening.
The Swede eventually took the third set 6-2 to progress to today's quarter-finals.
Del Potro survived a scare before battling past Latvian Ernests Gulbis to set up a quarter-final against Serbian Viktor Troicki, who is shaping up as a genuine dark horse for the title.
Gulbis took the first set 6-4 and had the world No 9 under pressure at 4-4 in the second. But the Argentinian raised his game, breaking Gulbis in the ninth game and serving out the set before steam-rolling his tiring opponent 6-1 in the third.
Del Potro said he finally found some rhythm after making the crucial break in the second set.
"After that I started to play my game. I served much better and he was tired. I don't know what happened with him but I improved my game and the third set was easier than the start of the match."
Troicki, the world No 53, also came from a set down to defeat Del Potro's close friend and fellow Argentinian Juan Monaco 3-6, 6-4, 6-2.
Del Potro will be happier facing Troicki, whom he beat in straight sets in their only meeting in a final of a tournament in Washington last year.
After struggling to get his game going against Gulbis, the tall right-hander found his range with his serve, dropping just a handful of points in the third set.
He felt "a little tired" after the match but expected to be better for the hit-out when he faces Troicki second up on centre court today.
Troicki was one of several to suffer in the heat as he edged to a 3-6, 6-4, 6-2 victory over Monaco.
"I was feeling dizzy. I wasn't used to it because in Europe where I trained in December it was pretty cold."
The 6-3, 6-3 defeat by Del Potro in Washington was Troicki's first appearance in an ATP final and came during a stretch when the Argentinian won 23-straight matches and four consecutive titles.
Troicki may have lost that encounter but he believes he learned enough to trouble Del Potro today.
"I gave it everything and he was a little bit better that day," Troicki said.
"I will have to play aggressive [today]. He is a player who will take his chances and go for his shots. I will have to move him around because he is a pretty big guy, but I think that is his weakness."
Sixth-seeded American Sam Querrey will face Spanish fourth seed Almagro in the first match of the day. Querrey also had to come from behind to beat Frenchman Gilles Muller in three sets in what was a tempestuous match on an outside court.
The big-serving American dropped the first set 3-6 but took the next two comfortably to progress.
"My body language and attitude wasn't the best," Querrey said after a match in which he lost his cool several times.
"I was getting a little frustrated. Hopefully I can change that [today].
"I'm looking forward to it. [Almagro] hits the ball really heavy with a lot of spin. He's got a great one-handed backhand so I've got to be aggressive and take some chances."
After struggling past Frenchman Marc Gicquel 6-7 (3), 6-4, 6-4, 2007 champion Ferrer will play either defending champion Philipp Kohlschreiber or former world No 1 Juan Carlos Ferrero.
Soderling will play American qualifier John Isner, who beat countryman Robby Ginepri in a three-set thriller on court six.