By Simon Cambers

Andy Murray pinpointed his battling qualities as the key factor in his 6-7 6-4 7-6 win over Ivo Karlovic in the final of the San Jose Open on Sunday.

The 19-year-old Scot had to come from a set down, and a break down in the second set, to win his second ATP Tour title in a battle lasting more than two and a half hours.

His straight-sets win over top-seed Andy Roddick followed two tough three-set battles against Dane Kristian Pless and Lee Hyung-taik of South Korea.

Murray admitted he had to dig deep to overcome the challenger of the big-serving Croat in the final.

"On a court (as fast as) this, I've had to play some big servers so it's about mental strength," Murray said.

"You have to play a great tournament to win, regardless of how well you're hitting the ball. But you do have to strike the ball pretty well to win an ATP tournament and I think I did that this week."

After his victory in San Jose last year, Murray suffered a slump in form with early defeats in several tournaments until Wimbledon, where he reached the last 16, which included a win over Roddick.

Murray said he hoped to avoid the same kind of let-down this time.

"I think I have more experience this year," he said.

"I am looking forward to the clay-court season this year. Last year I lost in three sets in Indian Wells, Miami, Monte Carlo and Barcelona.

"This year I have won all the three-set matches I've played. So that's the key, sticking in there in tough matches."