As the first week of Wimbledon continues to deliver stunning upsets with seeded players being dispatched left, right and centre, the fireworks continued off-court with former Wimbledon champion Marion Bartoli delivering a brutal assessment of the chances of two players still left in the draw, Australian firebrand Nick Kyrgios and mercurial Frenchman Gael Monfils.Kyrgios, who impressively overcame the challenge of Robin Haase in straight sets in the second round, has been tipped by many to make a serious impact in the second week of the prestigious grass court event.The 15th seed from Australia has had a chequered career, notable more for numerous spats with umpires and even fellow players than for consistent performances on the court.His big serving game is seen by many as ideal for Wimbledon, but Bartoli, speaking on BBC's coverage of the tournament, was dismissive of his prospects.Questioned about the chances of Kyrgios being a Grand Slam champion, she replied: “I don’t think so.“Just because his work ethic is just not good enough to win a Grand Slam.“And even when Rafa and Roger will eventually retire, the field is just too strong. And all of the other players just put so much hard work (in) to be there.“Even if he has all the talent in the world – and I’m defnitiely not questioning that – I don’t think he will be able to put seven matches in a row.”Kyrgios was quick to respond to the stinging analysis from Bartoli with a sarcastic tweet complete with a thumbs up emoji.

Bartoli also had harsh words for her compatriot Gael Monfils.

The 31-year-old who also progressed smoothly to the third round has endured a torrid year and currently languishes at 44 in the rankings, but the former top 10 player has given signs this week that he may be close to recapturing some of his best form.

His career has disappointed many experts who felt that his exceptional athleticism and on-court wizardry should have seen him compete more often for major titles over the last decade.

When fellow commentator and tennis legend John McEnroe asked Bartoli whether Monfils and Kyrgios shared similarites, she responded in blunt fashion.

“Absolutely (I do). And that’s why Gael has never won a Grand Slam as well and it’s a true shame because those kids have just so much potential,” she said.

“It’s really, in a way pathetic, to see them just being (childish). It just seems like they can’t grow up. They can’t become men they just can’t take charge of their own lives.

“I wish Gael had done it before and I truly hope Nick will be able to get it together at some point. I don’t know what he needs … maybe a wake up call to see he’s going to waste his life if he keeps on acting like that.”

Such incendiary words may be all the motivation Monfils and Kyrgios need to confound their sceptics.

It will add another layer of intrigue to what has already been a fascinating opening week at SW19.