World number one Rafael Nadal and third seed Roger Federer made smooth progress into the last 16 of the Sony Ericsson Open in Miami.
Nadal saw off fellow Spaniard, and good friend, Feliciano Lopez 6-3 6-3 after Federer had earlier beaten Argentine Juan Monaco 7-6 (7-4) 6-4.
Seventh seed Tomas Berdych joined them in round four with a 7-6 (10-8) 7-5 defeat of Carlos Berlocq.
Second seed Novak Djokovic and in-form Juan Martin del Potro won on Sunday.
Federer will next play Belgian Olivier Rochus, who saw off 13th seed Mikhail Youzhny 1-6 6-3 6-3, while Nadal awaits the winner of the match between Alexandr Dolgopolov and Jo-Wilfried Tsonga.
Nadal said after his win over Lopez that he was more concerned about landing his first title of 2011 than defending his number one status or the ranking points he accrued at this stage last season.
"I know I'm number one in the ranking right now, but I am number six this year. I didn't play for a month," said the 24-year-old.
"For me, every year I start from zero. Right now I am number six, and I would love to play well in the next tournaments and have the chances to be in a better position."
After edging past Monaco, Federer claimed he was happy enough with his performances towards the end of 2010 and in the opening months of this year.
Asked whether being the third seed in Miami has affected his approach, he said: "I've been in the semis with Rafael beforehand, so it's not something that's completely new to us.
"People talk about it like it's not been a good last six, seven months [for me] just because I'm number three in the world.
"But Rafa and Novak have been exceptional of late, and I've done really, really well. So it's up to me to step it up or just maintain that level of play and I'll get my chance."
Federer will face his friend Olivier Rochus in the fourth round after the Belgian pulled off a shock by beating Russian 13th seed Mikhail Youzhny 1-6 6-3 6-3.
Rochus, who stands 5ft 5in, is a player Federer knows could cause anyone problems.
"He has an amazing touch and feel out on the court, great playing sense, when to play which shot," said the Swiss.
"Even though he's a small guy out there, he knows how to use his weapons and his feel.
"He's a great tactician. I enjoy playing against him."
Czech seventh seed Tomas Berdych was pushed hard by Argentinian Carlos Berlocq but scraped through their match 7-6 (10-8) 7-5.
Last year's Wimbledon runner-up will play Germany's Florian Mayer in the last 16.
Unseeded Mayer beat Spain's 11th seed Nicolas Almagro 6-1 3-6 6-1, but his compatriot Phillip Petzschner was knocked out, losing 6-3 6-3 to Serbian Janko Tipsarevic.
France's Gilles Simon came through against Pablo Cuevas of Uruguay 4-6 6-1 6-2.