Roger Federer has chosen to skip the clay court swing of the season for the second consecutive campaign in order to be in peak physical condition when the grass court events come around later in the year.

The Swiss ace played four events thus far in 2018, he defended his title at the Australian Open and added another at the Rotterdam Open, which saw him take over the world number one ranking from long-time rival Rafael Nadal. But Federer failed to defend his titles at Indian Wells and Miami, which saw him surrender top spot to the Spaniard.

Nadal’s title wins in 2017 began at the start of the clay court campaign, where he won titles at the Monte Carlo Masters, the Barcelona Open, Madrid Masters and the French Open. He is currently number one, but has to defend his titles to remain at the top and Federer’s coach Ivan Ljubicic believes the pressure is now on the Spaniard to continue the form he displayed last year.

The one difference from 2017 is that last year Nadal came into the clay court season having made it to the finals of the Australian and Miami Open, while he is yet to complete a single tournament in 2018 owing to a hip injury that he sustained during the first major of the year in Melbourne. The 16-time men’s singles Grand Slam champion is playing his first ATP event this year, but is considered the favorite to win his 11th title at the ongoing Monte Carlo Masters.

Nadal will have to defend his title at the principality to remain the world number one and despite being the favorite, Ljubicic is certain he will be under pressure to emulate his form from 2017 when he absolutely dominated the clay court campaign.

“Rafa's period is coming, last year he did so well: he won in Monte Carlo, Barcelona, Madrid, reached quarters in Rome and won Roland Garros,” Ljubicic said, as quoted on Tennis World USA. “Now he is under pressure, he has to defend his results, his points. He may be the ultimate challenge on clay. In Monte Carlo, he won ten times and he is the favorite, he is in a great form.”

Ljubicic also discussed Novak Djokovic’s comeback and has no doubt the Serbian will be back in form for the major titles sooner rather than later. The 12-time Grand Slam champion lost in the second round at both the Indian Wells and Miami Masters recently, but it was clear that he was not 100 percent fit following his return from a long-term injury absence.

Djokovic underwent a minor procedure to repair his elbow injury after the Australian Open in January, and Ljubicic is aware it takes time to get back to full fitness.

“You forget that he was injured, he underwent surgery, it takes time,” he said about Djokovic. “But it's impressive to see him in this situation, he lost two opening rounds in Indian Wells and Miami, but it's just a matter time when, and not if, he comebacks.”

Nadal and Djokovic have been drawn in the same half at the Monte Carlo Masters and could face each other in the quarter-finals if results go according to plan. The duo will be in action Wednesday with the Spaniard playing his first match against Aljaz Bedene, while the Serb will take on Borna Coric after winning his first match against Dusan Lajovic.