Rafael Nadal had to withdraw due to an ab injury leaving the No. 1 ranking for now to Novak Djokovic.
Spaniard Nadal, who has not played since retiring injured in the U.S. Open semi-finals, cited an abdominal injury.
The return of Djokovic at the first line in the ATP ranking was the natural completion of his flawless game in the second half of the season.
The Serb, who will officially return to the summit of world tennis next Monday after Rafa Nadal's withdrawal from the tournament through injury, was outclassing Dzumhur when the Bosnian was forced to retire with an injury in the second set of their third round clash.
But in the past few days, I started to feel a little bit [of an] abdominal [injury], especially when I was serving. "I know something very bad happened inside there", Nadal said. He stated after his loss in Miami to Frenchman Benoit Paire that it was "just impossible at the moment" to play his best tennis. "I don't want to get into details but I think it's a minor thing". "I had a commitment since one year to play there", Nadal said. "I would love to be in London of course. I checked with the doctor and the doctor recommended I did not play".
Bulgarian ninth seed Grigor Dimitrov, who is working with USA legend Andre Agassi in Paris, went through with a 7-6 (12/10), 6-4 victory over Spain's Roberto Bautista Agut.
There were also wins on Wednesday for defending champion Jack Sock, Alexander Zverev, Kevin Anderson, Diego Schwartzman and Borna Coric.
No. 8 John Isner, No. 9 Grigor Dimitrov and No. 10 Kei Nishikori also won.
World number 57 Herbert was beaten by Kazakhstan's Mikhail Kukushkin in three sets (3-6, 6-3, 7-5) while Jeremy Chardy, ranked 40th, lost 6-4, 6-4 to Spain's Fernando Verdasco.
Isner and Nishikori are competing with No. 5 Marin Cilic and No. 6 Dominic Thiem for the last two spots for the ATP finals.