Fish has made semis in Auckland and Memphis this year

The American fourth seed had chances to go 5-3 ahead in the second set but squandered two break points.

"Mariano is a great clay court player," said Fish. "I didn't play poorly. I gave myself chances and for whatever reason it didn't work out."

Zabaleta will play Jurgen Melzer after his 6-4 6-2 win over Victor Hanescu.

Fifth seed Melzer, who was beaten by Fish in the final last year, had little trouble in overcoming the Romanian to reach the last eight.

Third seed Tommy Haas reached the second round after rallying from a set down to defeat American Sam Querrey 3-6 6-3 7-5.

The German was also down a break in the deciding set but broke in the seventh game and again in the 11th to go 6-5 ahead.

"Sam served huge at times where I didn't have much chance to do anything," he said.

"I was way behind the baseline just trying to react and get the balls back."

Frenchman Sebastian Grosjean failed to make the second round after losing 6-4 6-4 to Diego Hartsfield.