Tennis author Bastien Fachan has sparked off a debate on Twitter about the best active player on the ATP Tour to have never won a Masters 1000 title, suggesting the likes of Casper Ruud, Nick Kyrgios and Gael Monfils.

Fachan, whose biography on the Big Three was published in November last year, started the discussion after world No. 5 Jannik Sinner won his first Masters 1000 title at the National Bank Canadian Open in Toronto last week.

"With Jannik Sinner now out of future discussions, who's the best active player never to win a Masters 1000?" he wrote.

Underneath his question, Fachan wrote 'A short list' of players he thought were worthy of being called the best active player to have never won a Masters 1000 title, with his criteria being 'based on CV/peak level…'

The list goes as follows:

Kei Nishikori

Milos Raonic

Casper Ruud

Gael Monfils

Nick Kyrgios

Kevin Anderson

Richard Gasquet

Matteo Berrettini

Fernando Verdasco

In the comments, many fans were in support of Ruud, due to him having already reached three Grand Slam finals.

"Seems likely Casper [Ruud] will win one on hard court and even more likely on clay," wrote one.

"Ruud. I think It's Just a matter of time," commented another.

Meanwhile, other fans gave their vote to 2022 Wimbledon finalist Kyrgios, despite the fact that he has missed most of this season due to injury.

"Kyrgios isn’t *really* active anymore, but anyway, he’s the obvious answer in terms of peak level. I don’t like him, but his talent is stratospheric," wrote one.

Meanwhile, another favored former world No. 6 Monfils, saying they hope he wins one before retiring.

"I really hope Monfils wins one before he retires," they commented.

Other fans talked about the list as a whole, saying some of the players on it would have won at least one Masters 1000 title if they hadn't peaked during the height of the Big Three's era:

"Lot of good players. I’d go with Kando [Kevin Anderson] or Milos [Raonic] and then Nishi [Kei Nishikori]. They all wouldve won at least one but for the era they played in.

Verdasco, gasquet, monfils next who might’ve won one but for their era.

Ruud, Berrettini, Nick [Kyrgios] all still could."