Rafael Nadal responded furiously to a question about whether his recent marriage had affected his on-court focus after he was beaten by Alexander Zverev in their opener at the ATP Finals in London.

Spanish world number one Nadal went down in straight sets, 6-2 6-4, against the German youngster in a one-sided encounter at the O2 Arena.

Nadal, 33, wed childhood sweetheart Xisca Perello at a ceremony in Spain last month but branded as “bullsh*t” a question by one journalist as to whether his new marital status had caused him to become “distracted.”

Ruthless performance from @AlexZverev 🔥Last year’s champion triumphs 6-2, 6-4 & defeats Nadal for the first time in his career 👌🎥: @TennisTV | #NittoATPFinalspic.twitter.com/ekbv1wBGvr — ATP Tour (@atptour) November 11, 2019

"Honestly, are you asking me this? Is [this] a serious question or it's a joke? Is it serious?" the 19-time Grand Slam winner fumed.

"Okay. I’m surprised, it's a big surprise for me you ask me this after I have been with the same girl for 15 years and having a very stable and normal life. It doesn't matter if you put a ring on your finger or not. In my personal way, I am a very normal guy.”

After asking the journalist how long he had been with his wife, and getting the reply that it had been 30 years, Nadal said: "And before? Ah, maybe before you were not sure. That's why.

"Okay. We move to Spanish, because that's bullsh*t. Thank you very much.”

"We move to Spanish now because that's bull****"😮🥊 Rafael Nadal v journalist 🥊😮 pic.twitter.com/lVwuLeEgdl — Eurosport UK (@Eurosport_UK) November 12, 2019

Nadal headed into the London season finale with doubts over his fitness, after being forced to withdraw from the Paris Masters at the start of the month due to an abdominal injury.

He looked out of sorts against Zverev, the reigning ATP Finals champion, and will now face a major struggle to keep his world number one status from the hands of Serbian star Novak Djokovic.

READ MORE: Novak Djokovic destroys debutant Matteo Berrettini in Nitto ATP Finals curtain-raiser

Nadal next faces Russian world number four Daniil Medvedev in their group match on Wednesday, in a repeat of the US Open final which Nadal won in an epic five sets.

Medvedev, 23, also lost his opener in London, going down in a tight encounter to bitter rival Stefanos Tsitsipas.