The 21-year-old, sidelined since May by a hamstring injury he suffered at the French Open, battled past Slovakia's Lukas Lacko 7-5, 7-5 in the opening round at the LA Tennis Center.
“I didn't care how I played,” Gulbis told reporters after firing down 11 aces on the hardcourt surface. “It was a tough win because I didn't feel the ball really well.
The Latvian, the youngest player in the draw, will next face either Colombian Alejandro Falla or Slovakia's Karol Beck.
Germany's Rainer Schuettler advanced when seventh seed Horacio Zeballos of Argentina retired because of an injured left shoulder when trailing 6-3, 3-0.
In other matches, sixth-seeded Serbian Janko Tipsarevic crushed Colombia's Santiago Giraldo 6-1, 6-0 and Israel's Dudi Sela won a see-saw encounter against Belgian Xavier Malisse 6-1, 4-6, 6-3.
British world number four Andy Murray is the top seed for this week's $ 619,500 event with defending champion Sam Querrey of the US seeded second, Cypriot Marcos Baghdatis third and Spaniard Feliciano Lopez fourth.
The top four seeds all get byes into the second round.
Somdev in main draw
Somdev Devvarman scored a straight set win over Ecuador’s Giovanni Lapentti to qualify for the singles event of the USD 619,500 Farmers Classic , adds PTI from Los Angeles.
The third seed Indian beat his unseeded rival 6-2, 6-4 in the third and final round match of the qualifiers. His first-round opponent in the main draw is a local qualifier Steve Johnson.
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