Cameron Norrie has apologised after he threw his racquet and accidentally struck a spectator during his straight-set loss to Facundo Diaz Acosta at the Auckland Classic.

British number two Norrie received a warning but avoided disqualification for the incident, which happened when he was 6-2 5-3 down.

After the former world number eight netted to give Argentina's Diaz Acosta match point, a frustrated Norrie tossed his racquet behind him and into the crowd.

The chair umpire checked the woman had not been injured before issuing Norrie with a warning for unsportsmanlike conduct.

"I was not meaning to do that and it is completely not me to do something like that," said Norrie, who grew up in Auckland.

"I apologised very quickly and I want to apologise in general. I'm not happy with how I behaved."

Diaz Acosta went on to secure a 6-2 6-3 victory just three points later.

"[The spectator] was laughing and I just said 'so sorry, I didn't mean to do that'. And she said 'yeah, I'm completely OK'. That was not a big deal," said Norrie.

"But as we saw with some other players, you can easily be defaulted if it catches them in the wrong spot or they're not looking or something."

Novak Djokovic was disqualified from the fourth round of the 2020 US Open after he accidentally hit a ball at a line judge.

Canada's Denis Shapovalov was defaulted for hitting the umpire with a ball during a 2017 Davis Cup tie against Great Britain, while in 2012 David Nalbandian was disqualified at Queen's after injuring a line judge by kicking an advertising board into his shin.