World number eight Maria Sakkari said she could smell "weed" on court during her straight-set loss to Rebeka Masarova at the US Open.
Sakkari, 28, was beaten 6-4 6-4 by the Spanish world number 71 in the first round of the final Grand Slam of the year.
The Greek was leading 4-1 in the first set at Flushing Meadows when she signalled to the umpire of the scent.
"Oh my god... I think it's from the park", said Sakkari.
Cannabis is a Class B drug in the UK and is illegal to possess, distribute, sell or grow but it is legal in New York State for adults 21 and older.
Sakkari's loss was her third successive first-round exit at a Grand Slam, as she also fell at the first hurdle at the French Open and Wimbledon this year.
Despite making her complaint to the umpire during the defeat, Sakkari insisted she was not using the smell as an excuse.
Sakkari said in her post-match news conference: "We were practising here yesterday and it was the same. It wasn't the smell that affected the scoring.
"It was just a comment because it was smelling quite a lot, but it has nothing to do with the match."
Meanwhile, Novak Djokovic will replace young rival Carlos Alcaraz as the men's world number one after a routine win on his US Open return.
Serbia's Djokovic, who lost the Wimbledon final to Alcaraz, won 6-0 6-2 6-3 against France's Alexandre Muller in Monday's night session in New York.
Djokovic, 36, was not allowed to play in the United States last year because he was not vaccinated against Covid-19.
He has returned knowing another title will be a record-equalling 24th major.
Matching Australian Margaret Court's all-time tally is Djokovic's target and he made a statement start by breezing past 84th-ranked Muller.
"I started tremendously well, we started quite late but nevertheless I was excited to go out on the court - it has been a couple of years," said Djokovic, who will spend a record-extending 390th week at the top of the ATP rankings.
"In the second and third sets I dropped the level of my serve and I had to work for the points a bit more. Nevertheless I played great and I liked the level."
