"Not a great start to 2023 and few tough days in Melbourne," he wrote on Twitter on Thursday.

Both world No. 1s were among a slew of current top players and tennis legends who took to social media to celebrate the 20-time Grand Slam champion.

A day after the 23-time Grand Slam winner waved farewell at the US Open, celebrities, athletes and figures from the tennis world and beyond were still paying respects to the "GOAT".

How would you describe the 23-time Grand Slam champion? Naomi Osaka, Carlos Alcaraz, and Coco Gauff drop some superlatives you can use.

The Croatian made his last match a lot longer than it needed to be, which could doom him against his younger, more energetic opponent.

The Croat is 2-0 against Paul, and he also happens to be playing some fantastic tennis in 2022.

He’s just the fifth active man to reach that milestone after Roger Federer, Rafael Nadal, Novak Djokovic and Andy Murray.

As of Wednesday evening, there had been no change in the AELTC’s position on testing, leaving it up to the players to monitor their own health.

“The dream is over for this year. But I will be back stronger,” wrote the 2021 finalist after breaking the unfortunate news on his social media.

The Spaniard passes the Swiss for No. 2 on the all-time career prize money list, now trailing only Novak Djokovic. Meanwhile, Marin Cilic also hits a big prize money milestone.