United States qualifier Austin Krajicek bounced back from his loss to Denis Istomin at Indian Wells to eliminate the Uzbek from the Miami Open on Wednesday.
In their second-ever meeting on the ATP Tour, Krajicek gained revenge for his 7-6 (7-5) 6-4 loss to Istomin earlier in March, triumphing 6-4 6-4 on a strong day for the locals on the hard courts of Miami.
Krajicek was one of five Americans to advance to the second round of the ATP 1000 event, with not one local losing.
The world number 146 claimed the only two breaks of the match, while he lost just five points behind his first serve - matching 63rd-ranked Istomin's aces tally with four to claim victory in one hour, 14 minutes.
Jack Sock continued his strong but late start to the year, overcoming Go Soeda 6-3 6-4 in just 68 minutes.
Sock, who missed the first couple of months after hip surgery, played his first tournament of 2015 at the BNP Paribas Open in Indian Wells, where reached the fourth round before losing to finalist Roger Federer.
The other locals to triumph on Wednesday were Donald Young, Sam Querrey and Tim Smyczek.
Young progressed thanks to a neck injury to Yen-hsun Lu with the American leading 5-1 in the first set, Querrey trumped Victor Estrella Burgos 6-4 6-3, and Smyczek defeated Adrian Menendez-Maceiras 4-6 6-3 6-4.
James Duckworth was the only Australian to get on the winners' list, edging out fellow qualifier Damir Dzumhur 6-3 3-6 6-3, with Marinko Matosevic going down to Jarkko Nieminen 6-3 6-3 and Carlos Berlocq eliminating Thanasi Kokkinakis 6-4 3-6 6-2.
Nicolas Almagro defeated Sergiy Stakhovsky 6-3 6-7 (3-7) 6-4 to set up a second-round encounter with fellow Spaniard and second seed Rafael Nadal, who received a bye through the first round.
Germany's Jan-Lennard Struff recovered from a set down to defeat compatriot Benjamin Becker 3-6 7-6 (12-10) 6-4, wildcard Hyeon Chung was a 6-0 4-6 6-4 winner over Marcel Granollers and Dusan Lajovic retired 4-2 down in the third set to hand fellow Serb Filip Krajinovic victory.
In other results, Dominic Thiem trumped Diego Schwartzman 7-6 (7-0) 7-5, Albert Ramos-Vinolas cruised past Joao Sousa 6-2 6-2, Juan Monaco outlasted Ruben Bemelmans 7-5 6-7 (4-7) 6-4 and Robin Haase defeated Kyle Edmund 6-2 6-2.