Emma Raducanu's coach Mark Petchey has said heavier tennis balls are among things affecting the British number two's attempts to rejoin the world's elite players.
Raducanu exited the French Open after being outclassed by five-time Grand Slam champion Iga Swiatek 6-1 6-2 in the second round on Wednesday.
The 2021 US Open champion is ranked 41st in the world and has won just one of her nine career matches against top-five players.
"From my point of view, it's tough on Emma as I still feel everyone is living in 2021," said Petchey, who has been coaching Raducanu in an "informal" arrangement since March.
"The games have changed massively," said Petchey.
And exaggerating to make the point about heavier balls, he continued: "The balls are four times heavier than back in 2021 and Emma isn't the biggest hitter out there.
"If you can't put the ball through the court on a windy, heavy clay court day against someone like Iga, you're going to get into all sorts of trouble."
Petchey, a former British number one, coached an 18-year-old Andy Murray for 10 months helping him break into the top 50 in 2006 and also trained Raducanu during the pandemic summer of 2020.
