David Ferrer and Andy Murray, the top two seeded players in the Mexican Open, advanced to the second round on Tuesday while American and third-seeded John Isner became the first major casualty of the tournament, losing 7-6 (4) 7-6 (5) to Croatia's Ivo Karlovic.
Ferrer, the favorite in Acapulco, had a convincing 6-2, 6-3 victory over Kazakh Mikhail Kukushkin while Murray overcame a sluggish start and claimed a 3-6, 6-1, 6-2 win over Pablo Andujar, from Spain.
"I had a difficult start, it was 10 minutes in the match and I was down 5-0, but I started to play more aggressively to get the win and hopefully I can have a good week here", Murray said. "The first set was extremely challenging, he was dictating the points, but later on he was getting tired and put the pressure on him".
Murray, who played for the first time ever in Latin America, lost his first three service games and fell into a 5-0 hole, but came back strongly to set up a match against Joao Sousa of Portugal.
"I played Joao once in Australia, he was new on the tour then and he has improved. He's playing good tennis, he's good on clay and on hard courts", added Murray. "He plays similar to Pablo, hopefully I can play aggressively from the start."
In the round-of-16, Ferrer, who is trying to win on Mexican soil for the fourth time in his career, will play Spanish compatriot Feliciano Lopez.
"I*m not thinking about the final, I'm only in the second round", Ferrer said. "Now I'm only thinking about playing my best tennis against Feliciano Lopez, he*s a good player I need to give my best to beat him".
Ferrer, who now has a 4-0 record against Kukushkin, is coming off an impressive run in the past two weeks of the ATP tour, winning the Buenos Aires tournament and reaching the semifinals in Rio de Janeiro last week.
"Playing in Buenos Aires was not in my plans", said Ferrer who replaced his countryman Rafael Nadal in Argentina. "I'm tired, but I will not be making any excuses, I need to take a rest now and get well for the rest of the tournament".
Earlier, Karlovic served 15 aces to Isner fired eight in a match between two of the game's biggest servers.
"I'm very disappointed," a visibly upset Isner said after the match. "I wanted to do well in here, is a good surface for me, but I played against a guy who played well against me".
The 2.11-meter (6-foot-11) Karlovic now has a 3-2 career record against the 2.08-meter (6-foot-10) Isner, who's ranked 13th in the world.
Sousa of Portugal came back to defeat Frenchman Adrian Mannarino 1-6, 6-2, 6-2.
South Africa's Kevin Anderson downed Stephane Robert of France 6-2, 7-6 (7) and will next play America's Sam Querrey. Also, Alexandr Dolgopolov, from the Ukraine, beat Canada's Vasek Pospisil 6-2, 6-2 and seventh-seeded Ernests Gulbis had a 6-1, 6-1 victory over Taiwan's Yen-Hsun Lu.
Latvia's Gulbis won his fifth career title last week in Marsella.
On the women's side of the combined ATP-WTA tournament, top-seeded Dominika Cibulkova had a 6-3, 6-4 win over Urszula Radwanska, from Poland, Eugenie Bouchard eliminated Shahar Peer from Israel 6-2, 6-2, American Victoria Duval had a 6-2, 6-4 win over Czech Iveta Melzer and Estonian Kai Kanepi prevailed 6-1, 3-6, 6-2 against Jana Cepelova, from Slovakia.