NOVAK DJOKOVIC

Here's how grunting affects player's performance.

Serbian begins campaign at SW19 against Martin Klizan on Tuesday [4 July] after turbulent 12 months.

Djokovic has already won his first title since partnering up with Agassi in late May.

Tennis' big four have been struggling with various issues in recent months.

World number one, bothered by a persistent hip issue, lands in the same half of the draw as Rafael Nadal.

High-profile quartet secure top four seeds at a grand slam for the first time in three years.

The former tennis player does not expect to see a surprise winner at SW19 this year.

Swiss to avoid that heavyweight trio until semi-finals at SW19 after defeating Mischa Zverev in Halle.

Struggling 12-time Grand Slam winner has accepted a wildcard for next week's Aegon International.

British star's Wimbledon preparations took a big hit with shock first-round defeat to Jordan Thompson.

Murray has been the world number one for 32 weeks.

Djokovic has dropped out of the top two in the world rankings for the first time since 2011.

Briton admits performances in 2017 have not been good to remain atop of the ATP rankings.

Djokovic most recently crashed out in the French Open quarter-final.

Spaniard won his 10th French Open crowd by beating Stanislas Wawrinka.

Defending champion knocked out of French Open by Dominic Thiem.

Mark Petchey believes that troubled Serbian is "too good not to return to his best" after French Open exit.

World number one faces fellow three-time major winner Stanislas Wawrinka in French Open semi-finals.

The Austrian bested Djokovic in straight sets to reach second consecutive semi-final in Paris.

The defending champion accused of giving up after losing third set 6-0 at Roland Garros.

Djokovic appointed Andre Agassi as his new coach ahead of the 2017 French Open.