Roger Federer (right) returns a ball to Denis Istomin of Uzbekistan during a training session at Wimbledon. Photo: Peter Klaunzer/EPA

LONDON – Roger Federer's choice of practice partner at a serene, sun-drenched All England Club this week offered a reminder that the Swiss great is mortal on the most famous of tennis lawns.

Ukraine’s Sergiy Stakhovsky stunned Federer in the second round in 2013 - a year in which he failed to reach a Grand Slam final for the first time in 11 years.

Watching him five years on, just shy of his 37th birthday, saunter through a light-hearted hit with Stakhovsky on a pristine Court Three, cracking jokes and pinging effortless winners for the benefit of a few awe-struck ground staff, everything looked in place for yet another title run in south west London.

Federer did not drop a set last year as he ended a five-year wait for his eighth Wimbledon title, beating Croatia’s Marin Cilic in the final to move past the professional era record he shared with American Pete Sampras.

With his Grand Slam haul now at 20 after winning a sixth Australian Open title in January, also against Cilic, the king will take some shifting from his Wimbledon throne when Centre Court opens its doors on Monday. Having opted to miss the entire claycourt season to spare his knees a battering, Federer’s batteries will be fully-charged for Wimbledon.

Roger Federer takes a breather during his training session at Wimbledon on Thursday. Photo: Peter Klaunzer/EPA

He played nine matches in two weeks in Stuttgart and Halle, winning his 18th lawn title in Stuttgart before having his 20-match winning streak on grass ended by Croatian Borna Coric - one of the so-called Next Gen tipped to break the stranglehold that Federer and Rafael Nadal still exert on men’s tennis.

While he played down that defeat, it will definitely nag. “Being the defending champion always creates pressure,” Federer said after his loss to Coric. “I just really need to make sure I play great tennis from the get-go.”

Federer will be seeded one next week, despite slipping to two in the ATP rankings behind Nadal.

And while a strong favourite with the bookmakers, third seed Cilic is in superb form, three-times champion Novak Djokovic is enjoying a return to something like his best form, not to mention a resurgent Nadal lurks on the other side of the draw.

He will also be wary of the fearless young brigade who will be inspired by Coric’s win, one of whom is Canadian teenager Denis Shapovalov.

“Borna’s win didn’t surprise me,” Shapovalov said this week. “They are all human. They have all been beaten before. Obviously they are legends at this game to be where they are at their age. But anyone can lose on a given day.”