British number one Andy Murray was made to fight to beat big-serving Croatian Ivo Karlovic and reach the round of 16 at the Indian Wells Masters.

The 11th-seeded Scot put in an impressive display in California to overcome the world number 20 Karlovic 7-6 (7) 6-7 (3) 6-3 in two hours and 19 minutes.

Murray, who will next face Tommy Haas after the German beat Spaniard Fernando Verdasco 7-6 4-6 6-1, did well to slow down the 6' 10" Croatian's regular serve-and-volley repertoire, breaking Karlovic four times.

Despite an impressive victory against an opponent with one of the most imposing serves on the ATP Tour, Murray was disappointed with what was at times a frustrated display on court.

"I was disappointed with my attitude during the match, I was getting really angry and I haven't done that this year," he said.

"I was just in a bad frame of mind and you can sometimes snap out of it, but when you're playing someone who is as frustrating to play against as him, it's difficult.

"I was just happy with the way I came through in the end because I was not focusing as well as I should have been."

Though Karlovic struck first with a break of serve in the third game before opening up a 3-1 lead, Murray fought back with a break in the sixth followed by a love-service effort for a 4-3 lead.

As the opener went to a tie-break Murray remained in command before surrendering two set points in the breaker and finally clinching the first set on his third chance.

Karlovic, however, came out with renewed energy in the second set, breaking the world number 11 and speeding out to a 3-0 lead.

But the 29-year-old Zagreb resident, who fired a sub-par tally of 11 aces, was unable to serve out for the match at 5-3 with Murray breaking back before holding serve to level at 5-5.

Karlovic took the subsequent second tie-break thanks to some typically massive first-serves to send the match to a decider.

Murray then raced to his own 3-0 lead in the final set, before allowing the Croatian to break back in the seventh.

But at 4-3 the number one Briton earned what this time proved to be the decisive break before wrapping up the victory on his ensuing service game with a stupendous drop-shot on match point.

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Jeremy Stahl / Eurosport