Stan Wawrinka handed Grigor Dimitrov an agonising defeat at the Western & Southern Open, where defending champion Novak Djokovic was joined by Roger Federer in the third round.

Wawrinka prevailed against Dimitrov in a topsy-turvy clash at the ATP Masters 1000 tournament in Cincinnati on Tuesday.

Djokovic made a winning start to his title defence, while last year's runner-up Federer could not be stopped by Juan Ignacio Londero or the weather.

WAWRINKA COUGHS UP LEAD BUT STILL WINS

Stan The Man's gripping 5-7 6-4 7-6 (7-4) victory over Dimitrov had it all.

Wawrinka lost the opening set and squandered a 5-1 lead in the third as Dimitrov threatened a stunning comeback.

Dimitrov saved two match points in the process to level it at 5-5 before Wawrinka broke again but the three-time grand slam champion was unable to serve it out.

Wild. RIDE!

32 minutes after his first match point, @stanwawrinka seals his victory over Grigor Dimitrov 5-7 6-4 7-6(4). #CincyTennis pic.twitter.com/FaV448pxsx
— Tennis TV (@TennisTV) August 13, 2019

Wawrinka, though, raced out to a 4-0 lead in the tie-break and eventually closed out his fifth consecutive win against Dimitrov.

Next up for Wawrinka is qualifier Andrey Rublev, who upstaged 15th seed Nikoloz Basilashvili 6-7 (4-7) 6-4 6-2.

NOVAK VICTORIOUS IN FIRST MATCH SINCE WIMBLEDON TRIUMPH

Top seed Djokovic overcame a slow start as he saw off Sam Querrey 7-5 6-1 en route to the round of 16.

Djokovic was broken in the opening game of the match after double-faulting on three occasions, but the world number one was not to be denied.

Novak is BACK

Defending champ @DjokerNole pushes past Sam Querrey 7-5 6-1 to book his spot in round 3 at #CincyTennis pic.twitter.com/yWq4sn9K05
— Tennis TV (@TennisTV) August 13, 2019

The 16-time grand slam champion was appearing on the singles court for the first time since his remarkable five-set victory against Federer at the All England Club.

"The fact that I'm a reigning champion wasn't affecting me positively or negatively. There was just excitement to be back on the court competing because it's been quite a while since the Wimbledon final," said Djokovic, who meets Pablo Carreno Busta after the Spaniard outlasted John Isner. "But at the same time, I had the nervous start because I haven't played a match in four weeks. It took a while to adjust to his big game. I made three double faults in the opening game and didn't have the greatest of starts."

FABULOUS FEDERER EASES INTO LAST 16

Also featuring for the first time since losing an unforgettable fifth set 13-12 (7-3) to Djokovic in the Wimbledon final, Federer steamrolled Londero 6-3 6-4.

Federer only needed 61 minutes, excluding a lengthy rain delay, to keep his quest for an eighth Cincinnati crown alive.

Roger that!

7-time champion @rogerfederer speeds past Juan Ignacio Londero 6-3 6-4 in 61 minutes to book his spot in round 3 at #CincyTennis pic.twitter.com/EHDeN80cst
— Tennis TV (@TennisTV) August 14, 2019

"[I'm] very happy. I thought it was tricky with the rain delay and everything, but I'm happy to be back on the courts," Federer, who will face the winner of Wawrinka-Rublev, said. "It's totally different to the grass courts and the clay courts we have seen, so this is the beginning of a long, long hard-court swing. So it's nice to start off with a win."

Elsewhere, the likes of Daniil Medvedev, Roberto Bautista Agut, David Goffin and Denis Shapovalov advanced but Borna Coric bowed out.