The world number one was given the penalty at the end of the second set in the 6-4 6-3 6-4 win over Mikhail Kukushkin.

He later found out he had been also given one for overshooting the warm-up.

"I don't see a watch here. I don't see that countdown," he said.

"It's more difficult for me to understand what's going on. In Australia and Roland Garros, we have the watch here that we can manage to be under control."

Two-time Wimbledon champion Nadal was made to work hard against Kazakhstan's Kukushkin to set up a third-round meeting with Australian teenager Alex de Minaur.

'I needed that time'

Nadal has in the past asked for umpire Carlos Bernardes not to officiate his matches

Nadal's heart must have sunk when he saw who was in the umpire's chair for his match on Centre Court, with the Spaniard having had past run-ins with Carlos Bernardes and having asked for him not to officiate his matches.

In February 2015 Bernardes was in charge of a match in Rio de Janeiro when Nadal had put his shorts on the wrong way round and he asked to go to the locker room to change them but was told he would get a time violation.

On Wednesday Bernardes ruled Nadal had taken too long with his clothing once again.

"You know, I know I had to take the wristband, T-shirt, bandana out, change everything," he told a news conference.

"Probably I should go to the toilet. If I go to the toilet, I had plenty of time to change everything without the time violation. I decided to stay on the chair."

The first Nadal heard about the pre-match time violation was at the news conference.

He said he did not have a problem with the umpire penalising him or have a problem with him personally, but admitted they did have history.

"I can't say, I don't want this umpire," he said. "I just can ask if I believe that somebody's not doing the things fair with me or was not respectful for me, I just can ask if is possible to have another umpire.

"It is something that happened in the past. It is about what happened in Rio de Janeiro a couple years ago. For me personally it was disrespectful.

"It is not about the time. It is not about this kind of stuff. It is about the problem that I had with him in the past. It's about that bad moment. That's all. No problems with him. I respect when I am slow, accept the warnings."

Nadal tested by Kukushkin

While the final result goes down as a straight-set victory, this was far from simple.

Kukushkin, who beat British number one Kyle Edmund in the Eastbourne quarter-finals last week, showed he meant business from the opening game with his powerful forehand that seemed to take both Nadal and the packed Centre Court by surprise.

When his big shot worked, it was exquisite - he made 28 winners, nine more than Nadal, with most of them on his forehand.

But his 34 unforced errors meant he never really had a chance against the 17-time Grand Slam champion.

After wrapping up the first set when the Kazakh netted a forehand, Nadal was more ruthless in the second where he lost just four points on his serve.

But Kukushkin, who is coached by his wife, just would not give up and in the third went a break up for 3-1 before dropping serve in the next game.

He eventually succumbed to the inevitable when his forehand clipped the top of the net and bounced back to his own side as the crowd got to their feet to give the players a standing ovation.

Nadal marches into the third round but Kukushkin goes home £63,000 better off and with a lot of new fans.