Umpire Damien Dumusois accused Andy Murray of having "zero respect for what I do" during a heated exchange in the world number two's Monte Carlo Masters semi-final defeat to Rafael Nadal.

Murray won the first set against Nadal on Saturday, but was ultimately beaten 2-6, 6-4, 6-2 as the Spaniard moved to within one victory of a ninth title in Monaco.

The time taken between points by Nadal appeared to frustrate Murray, who was involved in a disagreement with Dumusois when trailing 4-1 in the decider, the official apparently unhappy with the ball being hit in his direction on more than one occasion.

"That's enough, Andy," said Dumusois as Murray approached his chair, prompting a quizzical reply from the Scot.

"You have zero respect for what I do. So that's fine, you can disagree, but no respect, I cannot accept that," Dumusois added.

"I go there, I check the mark, you hit the ball to me. [It is] the second time you do it, you did it again before in the chair, so that's enough."

Murray protested his innocence, accusing the umpire of "just making stuff up", only for Dumusois to respond: "You know you hit the chair. You know exactly why you did it. I'm not stupid, Andy."

In his post-match news conference, Murray played down the row, but acknowledged he had lost his cool.

"There were a few things that happened in the match," he said. "Obviously towards the end, he [Nadal] got the time violation for taking too long in that last game. You guys were watching. And, yes, you can draw your own conclusions from it. I don't know how much of a bearing any of that had on the outcome.

"That stuff always happens during matches. It doesn't always influence the outcome. But when you're losing at the end, it’s easy to get frustrated at things. That was it.

"I played a good match, but you have to obviously take chances against the best players. Also, Rafa is allowed to play well sometimes, too. So you have to give your opponent credit. He's one of the best, if not the best ever, on this surface. He played some good stuff and deserved to win."