The world’s top-ranked player had won 16 consecutive matches since his only loss of the season, in the French Open semifinals against Roger Federer on June 3.

The winning streak has taken its toll.

He was completely off his game against the fourth-seeded Murray, who won the first set 6-4 and was ahead 3-0 in the second when Djokovic decided just before the rain came that he couldn’t continue. Djokovic had his shoulder treated after he lost the first set, grimacing at one point.

Djokovic is a sensational 57-2 for the season after his first loss on hard courts.

It is Murray’s second title this season. The 24-year-old Scotsman also won at the Queen’s Club. He lost his other final to Djokovic at the Australian Open.

Djokovic felt worn-down heading into the final, the strain of all those recent matches catching up with him. He won the title at Montreal last week, setting a record with his fifth Masters series championship. The 24-year-old Serb said his loathing for losing was pulling him through matches.

It couldn’t take him far enough on Sunday.

Djokovic was off his game at the outset, repeatedly hitting forehands, backhands and volleys everywhere but in the court. Murray broke his serve to open the match and won 10 of the first 12 points.

Could Djokovic win another one while running on fumes?

By the end of the first set, he had his answer.

Murray was more well-rested, though not by choice. He lost in the opening round at Montreal a week ago, giving him unwanted time to relax and work on his game. The break seemed to help — he didn’t lose a set all week in Cincinnati.

With the crowd behind him, Djokovic got back into the match by breaking Murray to tie the first set at 3. Murray broke him right back, ending a long baseline rally by coming to the net for a put-away volley. Djokovic walked around the court with a blank expression, his mouth open.

His demeanor said he was in trouble.

Djokovic made 20 unforced errors in the first set, which ended when he dumped a routine forehand into the net. Djokovic squatted in disappointment, then went to his chair and took a timeout to have a trainer stretch his right arm and shoulder.

When the trainer pushed on the side of his rotator cuff with his thumb, Djokovic grimaced.

Murray broke him again to start the second set, an indication the shoulder wasn’t going to get better. Djokovic started protecting the shoulder on his follow through.

When Murray left him with an easy volley into an open court, Djokovic couldn’t get anything on his overhead return, smacking it weakly toward the net. That point gave Murray a 3-0 lead and forced Djokovic to accept that he wasn’t going to get a chance to keep his streak going.

The health of his shoulder will become an overriding question heading into the US Open, which starts on Aug. 29. Rafael Nadal is the defending champion, and he’s also got some issues — burned fingertips on his right hand that bothered him in Cincinnati.