Number one Rafael Nadal lived up to expectations as the Spaniard strives for a first Miami title. The top seed reached the last eight over Ukrainian Alexandr Dolgopolov 6-1, 6-2 in just 59 minutes.
"It was very, very, very humid. That's why I'm sweating a lot," said Nadal, who said the long wait in the locker room did not bother him as he finally went onto court.
It was a similar outcome for second seed Novak Djokovic as he won his 21st consecutive match of the season over compatriot and Davis Cup teammate Viktor Troicki 6-3, 6-2.
"I try not to think that he's my good friend, that that might affect my performance on the court," said Djokovic. "We are both professional, we both want to win the match."
Third seed Roger Federer did not get on the court until well after midnight - the latest start of his career came at 12:37 am - but wasted no time in a 6-3, 6-1 hammering of Belgian Olivier Rochus lasting just 51 minutes.
The Swiss earned his efficient win in the early hours of the morning to send his 2011 record to 21-3 as he beat his good friend and long time opponent for the eighth time straight.
"It was extremely hot yesterday, and then today really late," Federer said. "That's what tennis is all about.
"We don't know when we play and we don't have a set schedule, and so we have to be able to adapt and warm up several times for the match, because you never know what's going to happen beforehand."
Former US Open winner Juan Martin del Potro was at a loss for words after a disappointing fourth-round ouster at the hands of American Mardy Fish 7-5, 7-6 (7/5).
"It's difficult to say something now because I just lost a very, very tough match," said the Argentine.
"Maybe in two or three days I can say my level at the moment and what I expect for the future."
Spanish sixth seed David Ferrer beat compatriot Marcel Granollers 6-1, 6-2 and South African Kevin Anderson put out American John Isner 6-3, 7-6 (7/4).
Number seven Tomas Berdych battled to get past German Florian Mayer 6-3, 2-6, 7-6 (7/4) and next plays Nadal in a re-run of the 2010 Wimbledon final.
There was third-round disappointment for Jo-Wilfried Tsonga as the French 15th seed was unable to recover in his rain-interrupted match from Monday against Dolgopolov.
Dolgopolov finished off the final set to post a 6-7 (2/7), 6-4, 7-5 win and set up a date with Nadal.
In women's play, battling Kim Clijsters saved five match points to overhaul Serb Ana Ivanovic 7-6 (7/4), 3-6, 7-6 (7/5) to reach the quarter-finals.
Ivanovic, a former world number one and French Open champ, led 5-2 in the final set before second seed Clijsters began her fightback.
The Belgian rallied in championship style to earn her place in the last eight of the last hardcourt event prior to the start of the clay campaign.
"Because I have been on the tour for many years, you realise that you have to keep trying until the last point is played," said Clijsters. "In tennis, that's sometimes probably the frustrating part about it.
"It's never over until that last shot is played. Even if it's 5-1. Okay, you start a game 0-0. She has to win four points."
German hope Andrea Petkovic began fulfilling her promise with an upset of Serbian sixth seed Jelena Jankovic 2-6, 6-2, 6-4.
Federer's match was pushed back by an almost three and a half hour marathon women's match which was won by Russia's Maria Sharapova.
Sharapova, the 16th seed, was broken ten times and treated by a trainer after rolling her ankle as she outlasted Alexandra Dulgheru 3-6, 7-6 (8/6), 7-6 (7/5).