Djokovic, appearing in his 300th Grand Slam match, did drop his second service game to go 1-2 behind in the first set but broke back immediately.
Roger Federer will play the winner of the tie between France's Jo-Wilfried Tsonga and Croatia's Milos Raonic after receiving a bye in the first round.
Rafael Nadal's 2016 season was plagued by physical problems and he cut his campaign short in October to recover fully to target a return to Grand Slam glory in 2017
Novak Djokovic will face another Frenchman, Gael Monfils, for a place in Sunday's US Open final after the 10th seed downed compatriot Lucas Pouille 6-4, 6-3, 6-3
Second seed Andy Murray will face Czech 10th seed Tomas Berdych on Friday in what will be his 20th semi-final at the Majors.
Andy Murray, who is bidding to reach a seventh Wimbledon semi-final, revealed he will prepare for Wednesday's last-eight clash against Jo-Wilfried Tsonga by doing Gyrotonic yoga and pilates
Andy Murray, the 2013 champion, eased to a 7-5, 6-1, 6-4 win and will face French 12th seed Jo-Wilfried Tsonga for a place in the semi-finals
Jo-Wilfried Tsonga pulled out of the French Open with a groin injury while top seeds Serena Williams and Novak Djokovic both swept into the last 16
French tennis player Jo-Wilfried Tsonga said he pulled out of Rome Masters due to a training injury.
Roger Federer back in action this week after a 10-week layoff, started brightly as he breezed through the opening set. But Jo-Wilfried Tsonga fought back to to register a stunning win.
Seventh seed Nishikori won 6-4, 6-2, 6-4 in just over two hours on Hisense Arena and will face either world number one Novak Djokovic or French 14th seed Gilles Simon in the last eight.
Jo-Wilfried Tsonga noticed that the ball girl was unwell during the third set of his Australian Open match on Wednesday, so he paused before serving and walked over to see what was wrong.
Jo-Wilfried Tsonga suffered a 4-6, 6-3, 1-6 to Lukas Rosol in the Austrian Open second round.
The one-sided win in one hour, 18 minutes at the Qi Zhong Stadium gave Serbia's Novak Djokovic his ninth title of a season in which he also won three out of the four Grand Slam finals.
Jo Wilfred Tsonga reached his first Shanghai Masters final when he defeated Rafael Nadal 6-4,0-6,7-5 in a tense semi-final match.
Bouchard has not played since she slammed her head in a locker-room fall at the US Open, and she lasted just 10 games against Andrea Petkovic before feeling dizzy and having her blood pressure checked.
Jo-Wilfried Tsonga earned 250 points by clinching the Metz Open title, which will help him qualify for the ATP World Tour Finals.
Top seed Novak Djokovic defeated Feliciano Lopez 6-1, 3-6, 6-3, 7-6 in the quarter-finals of the US Open 2015.