A winner of 12 Grand Slam titles, the Serb has suffered a noticeable dip in form since winning his maiden French Open last June, relinquishing top spot in the ATP rankings to Briton Andy Murray five months later.
Novak Djokovic confirmed he will be coached by Andre Agassi at the French Open after being humbled by German youngster Alexander Zverev in the final of the Italian Open on Sunday.
Former World No. 1 and Wimbledon champion has emerged as the surprised as the surprise candidate to take over Novak Djokovic's coach, The Daily Telegraph reported.
The Serb, who turned 30 last month, will drop outside the top two for the first time since march 2011 on Monday -- quite a contrast to a year ago when his domination of men's tennis was complete after winning the French Open for the first time.