Adjustments aren’t enough for Andy Murray against Federico Delbonis

Andy Murray’s serve was failing him, and he was struggling with the steady diet of topspin shots he was getting from Argentine left-hander Federico Delbonis in their third-round match at the BNP Paribas Open. Murray, never comfortable on the slow, hard courts here or with the high bounces they produce, had changed things up before the tournament by stringing his rackets much tighter than he had for his recent Davis Cup matches. He also arrived later than usual.

Those moves weren’t helping him Monday, so he decided to change his strategy midmatch.

“I stopped going for my first serve. I tried to get a higher percentage of first serves in, which maybe was not the best decision. I did manage to get myself into a winning position,” said Murray, ranked second here and in the world.

“Also, I started returning from way further back. First couple of sets I was standing quite close in, was struggling a bit on the return, but I made an adjustment there and started returning much further back on the first and second serve, and that helped a bit.”

But not nearly enough.

“I think with the return it worked,” Murray said. “With the serve, it didn’t work so much.”

Delbonis, well-prepared and intent on playing to Murray’s forehand, had the better game plan and the better day. His 6-4, 4-6, 7-6 (3) victory over Murray was a stunner, a display of intelligence, creativity and nimble feet against a patient opponent who ranked 51 places above him.

Delbonis, 25, defeated then-No. 5 Roger Federer in the semifinals of the German Open in 2013 and defeated then-No. 9 Stan Wawrinka in the quarterfinals of the Geneva Open last year, so he knew he would be tested in different ways Monday from when he faces players outside the top four or five.

“It’s more mentally, I think. With all the crowd it’s a little bit more pressure, but I’m enjoying that kind of matches,” Delbonis said. “It’s like a challenge every time, and I happy to get it.”

Delbonis had two service breaks in the first set to Murray’s one, and the second set went on serve until the 10th game, when Murray broke him for the set.

“I think he moved better than what I thought,” Murray said of his expectations of Delbonis in their first career encounter. “I found it difficult to hit many winners, and a lot of times I felt like I was hitting good shots and he was tracking them down and defending well.”

Murray broke Delbonis for a 3-1 lead in the third set, held for 4-1 and was up, 30-0, in the sixth game but couldn’t put it away. That proved pivotal.

“He came out with some good passing shots. I could have done a bit more with the volleys maybe,” said Murray, who committed 44 unforced errors and had 25 winners.

Whatever he did, Delbonis proved more resourceful.

“I know he wants to be aggressive in that third set. I don’t do my job until the 4-1,” Delbonis said. “I have to play it more to his forehand. When I do that, I can break. I can play from the 4-2 to the tiebreak and I get a big win for that, you know.”

That game was the first of three straight won by Delbonis, to make it 4-4. Each then held, taking it to 5-5. Delbonis broke for a 6-5 lead but Murray broke back and sent it to a tiebreaker when Delbonis hit a forehand long.

Murray won the first two points of the tiebreaker and was ahead, 3-2, before he hit a backhand into the net to make it 3-3. With the crowd growing quiet in anticipation of the upset, Delbonis won the last four points and raised his arms in joy after Murray sent a forehand wide on match point.

“I have just never really found a way to get comfortable here throughout my career,” said Murray, who has reached the final here only once, in a 2009 loss to Rafael Nadal. “It’s a shame.” Not for Delbonis. “Was a big match, like, mentally,” he said. “For that tournament, for that surface, for me is the best win.”

helene.elliott@latimes.com

Twitter: @helenenothelen