Novak Djokovic's historic 23rd Grand Slam title triumph has left even his longtime rival, Roger Federer, in awe.

Speaking with his characteristic finesse, the renowned tennis icon described Djokovic's achievement as nothing short of "unbelievable."

Federer, who gracefully bowed out of professional tennis last year with an impressive tally of 20 Grand Slam victories, acknowledged Djokovic's ascent to the summit of tennis greatness.

In a riveting showdown at the French Open in Paris, Djokovic surpassed the record set by his fellow legend, Rafael Nadal, with his third triumph on the Parisian clay.

Federer, 41, took a moment at the Halle grass-court tournament to express his thoughts on the topic, albeit cautiously, as he refrained from labeling one player as the unequivocal greatest of all time.

Federer conceded, "It's hard to say." The weight of such a declaration weighed heavily on his words. He recounted an exchange he had with a close friend, seeking guidance on the matter.

"I asked a friend, what is more difficult, winning Wimbledon at 17, like Boris Becker, or the French Open at 36 like Novak?" Federer said.

The magnitude of these achievements left him pondering, and he concluded that the question remained shrouded in ambiguity.

The tennis maestro recognized the current era as an extraordinary time for both fans and players alike. "It's a great time to be a tennis fan but also a player," he remarked.

Federer's words carried the weight of his own experience and appreciation for the sport. As the guest of honor for Roger Federer Day at Halle, his sentiments ran deep.

Returning to the tournament that holds a special place in his heart, Federer emphasized the significance of his presence in Halle.

"It means a lot to me," he said.

With a record of 10 singles titles to his name, the Swiss maestro found solace in the familiarity of the tournament.

Halle, he explained, felt like a cherished second home – a sanctuary of success.

Immersed in the spirit of the occasion, Federer delighted his fans by spending over an hour signing autographs and engaging in selfies on the sun-drenched center court.

However, he made it clear that he did not miss the rigors of competitive play.

Reflecting on his absence from the heat of the action, Federer said: "Of course, you want to experience that again. But as long as you know your body cannot do it at this level, you don't feel the need to be out on the court."