The final week of 500-level tournaments in 2026 promises early challenges for some of tennis’ biggest stars.

Eight of the world’s top 10 men will compete across two ATP 500 events: the Erste Bank Open in Vienna and the Swiss Indoors Basel.

On the women’s side, world No. 1 Elena Rybakina leads the field at the Toray Pan Pacific Open in Tokyo.

Here are five first-round matches you won’t want to miss this week: 

Vienna: Carlos Alcaraz vs. Karen Khachanov

World No. 3 Carlos Alcaraz is competing in the Austrian capital for the first time since 2021. The Spaniard starts his indoor swing against US Open semifinalist and former World No. 8 Karen Khachanov.

Alcaraz lifted his 27th ATP title earlier this month in Tokyo before falling to Zizou Bergs in the third round of the Rolex Shanghai Masters. Khachanov reached the quarterfinals of the Almaty Open ATP 250 last week.

Sit back and enjoy 🍿

10 crazy points from the Alcaraz vs Khachanov EPIC!#QatarExxonMobilOpen pic.twitter.com/X8I0F91psv

— Tennis TV (@TennisTV) February 19, 2026

Alcaraz has never lost to Khachanov in their six meetings, but the Russian pushed the No. 2 seed to three sets in their two latest encounters. 

Tokyo: Naomi Osaka vs. Jasmine Paolini

Japanese superstar Naomi Osaka will cap her 2026 season in her home country’s capital. The 2019 champion kickstarts her campaign against two-time major finalist Jasmine Paolini. 

Osaka skipped the Wuhan Open to celebrate her 29th birthday with her daughter. Paolini reached the round of 16 at both Wuhan and Ningbo. 

Paolini is the World No. 35, her lowest ranking since 2023. But the Italian remains a formidable opponent and beat Osaka in their lone meeting last year at the Miami Open. 

Vienna: Frances Tiafoe vs. Lorenzo Musetti

ATP Finals hopeful Frances Tiafoe has a brutal round one opponent in Austria: Lorenzo Musetti, who just won his third ATP title in Lyon. 

A third career title for Musetti 🏆🏆🏆#GrandPrixAuvergneRhoneAlpes pic.twitter.com/BhBxeIPE30

— Tennis TV (@TennisTV) October 25, 2026

Tiafoe last competed in Shanghai, falling to eventual champion Alejandro Davidovich Fokina despite holding a match point. 

The American holds a 4-3 head-to-head edge over Musetti and won their last meeting in August at the Cincinnati Open.

FRIDAY NIGHT FOE 🔥

2024 runner-up @FTiafoe battles past Musetti 7-6 7-5 to reach the semi-finals! #CincyTennis pic.twitter.com/2bBtTM5rkK

— Tennis TV (@TennisTV) August 22, 2026

Musetti reached the semifinals in Vienna the last two years, while Tiafoe was the runner-up in 2021. The winner is projected to face year-end World No. 1 Alexander Zverev in the quarterfinals. 

Vienna: Tommy Paul vs. Andrey Rublev

Frances Tiafoe wasn’t the only American who received a brutal draw in Vienna. Tommy Paul will square off against Andrey Rublev in a rare round-one match between two top-25 players. 

Paul, currently No. 12 in the ATP Finals Race, reached the semifinals in Lyon last week. Rublev is on a three-match losing streak but owns a 5-1 H2H record against the American.

The winner of this first round blockbuster could face Carlos Alcaraz in the quarterfinals.

Basel: Arthur Fils vs. Giovanni Mpetshi Perricard

Get your maple leafs at the ready, it's time for a Canadian battle 🍁

Fils and Mpetshi Perricard may be BFF's, but the gloves are on as they battle it out in this Canadian showdown 👊 🇨🇦#NBO25 | @NBOtoronto pic.twitter.com/Cy5jzgcjQE

— ATP Tour (@atptour) July 30, 2025

Arthur Fils opens his Swiss Indoors campaign against his friend and occasional doubles partner, Giovanni Mpetshi Perricard. While the two young Frenchmen have never faced each other on the main ATP Tour, Mpetshi Perricard holds two wins over Fils at lower-level events.

Mpetshi Perricard, who captured the Swiss Indoors title in 2024 and broke into the top 30 soon after, has since fallen to No. 145. The 23-year-old snapped an eight-match losing streak by winning two qualifying matches in Basel.

Fils, the second seed in Switzerland, is targeting his sixth ATP title of the season—a result that would put him in prime position to qualify for the year-end championships.