Alexander Zverev has come a long way since losing in the final round of qualifying in his last appearance at the Erste Bank Open 500 in 2014.

A five-time champion this season, Zverev began his pursuit of a sixth title this year in Vienna on Monday with a 6-3, 4-6, 6-4 victory against Viktor Troicki.

The German, who is No. 3 in the Emirates ATP Race To London, is attempting to find his best form to close out his season on a high note.

Zverev took one hour, 47 minutes to get by the Serbian, extending his FedEx ATP Head2Head record over the veteran to 3-1. The 6’6” right-hander will next play the tricky Frenchman Gilles Simon, who defeated Ernests Gulbis, 6-3, 6-3. The 20-year-old holds a 3-0 FedEx ATP Head2Head advantage over Simon, with two of the three meetings going to a final-set tie-break.

Philipp Kohlschreiber earned his 30th tour-level victory of the season when he defeated fifth seed John Isner, 7-6(6), 6-4. The German overcame a break deficit in both the first and second sets, saving three set points in the opening tie-break.

“I played my best tennis with my back to the wall,” Kohlschreiber said. “Though it is rare that a player like him would give a match away once he is two breaks up.”

It is the 11th straight season that the German has reached the 30-win mark. The only players who own longer streaks of 30 wins per year are Rafael Nadal (14 years), Tomas Berdych (13 years) and Novak Djokovic (12 years).

The German evened his FedEx ATP Head2Head rivalry with the American at 4-4, winning for the fourth time in their past five meetings.

Kohlschreiber will next face qualifier Pierre-Hugues Herbert, who sent Bernard Tomic’s record on the season to 10-19 with a 7-6(4), 7-5 win.

The Frenchman, who earned his berth in the Nitto ATP Finals in doubles with Nicolas Mahut, snapped a six-match losing streak in tour-level main draws. And while he trails Kohlschreiber in their FedEx ATP Head2Head rivalry, 2-1, he triumphed in their last meeting at The Championships last year.

Richard Gasquet got his tournament off to a strong start with a 6-2, 6-3 win over fellow veteran Feliciano Lopez. That sets up a second-round clash against the winner of a blockbuster opener between second seed Dominic Thiem and Andrey Rublev, who has qualified for the inaugural Next Gen ATP Finals. That first-round match will begin Tuesday’s evening session.

No. 14 Juan Martin del Potro, +4

A convincing straight-sets triumph over top seed Grigor Dimitrov in the final of the Intrum Stockholm Open lifted Juan Martin del Potro into contention for a return to the Nitto ATP Finals, to be held 12-19 November at The O2 in London. Del Potro secured his 20^th ATP World Tour title and jumped four spots to No. 14 in the Emirates ATP Race to London by retaining his Stockholm crown. Read Report.

The Argentine has 2,135 points in the Race, 470 points behind eight-placed Spaniard Pablo Carreno Busta. The 29-year-old is looking to secure his first Nitto ATP Finals berth since 2013 as one of the top eight players to qualify for the season finale. He is fourth seed at the Swiss Indoors Basel this week.

No. 5 Grigor Dimitrov, +1

The Bulgarian, who is next in line to qualify for the Nitto ATP Finals, improved his chances with a run to his third Stockholm final. It was his first defeat in four ATP World Tour finals this season.

The 26 year old rose one spot above Marin Cilic to No. in the Emirates ATP Race To London with 3,560 points, just 25 points ahead of the Croatian. He could seal his debut berth at the Nitto ATP Finals this week when he the Erste Bank Open 500 in Vienna.

No. 15 Jo-Wilfried Tsonga, +7

A career-best fourth ATP World Tour title of 2017 for the Frenchman has further crowded the battle for Nitto ATP Finals berths. Tsonga’s straight-sets victory over Diego Schwartzman in the European Open final in Antwerp has catapulted him seven spots up to No. 15 in the Emirates ATP Race to London.

The 32-year-old Tsonga had already landed titles in Lyon, Marseille and Rotterdam earlier this year. Tsonga now has 2,055 points in the Race, 550 points behind Carreno Busta. He will attempt to make up ground in Vienna this week.

No. 29 Damir Dzumhur, +10

Damir Dzumhur’s love affair with Russia continued when the Bosnian and Herzegovinian clinched his second ATP World Tour title there on Sunday. The St. Petersburg Open champion improved to 10-0 on Russian soil this season with his VTB Kremlin Cup triumph by overcoming Lithuanian Ricardis Berankis.

With his confidence riding high, it marked Dzumhur’s third ATP World Tour final from his past seven tournaments. He will look to crack further improve on his career-high position in the Emirates ATP Rankings at Vienna this week.

Other Top 100 Movers This Week

No. 64 Federico Delbonis, +6

No. 82 Andreas Seppi, +8

No. 92 Ruben Bemelmans, +24

No. 93 Stefanos Tsitsipas, +26

No. 96 Julien Benneteau, +10

No.98 Mikhail Youzhny, +27