No.1 seed Aryna Sabalenka and No.5 seed Coco Gauff claimed straight-sets wins in the first round of the bett1open on Tuesday. They are each one win away from setting up a possible quarterfinal showdown later this week.

Sabalenka advanced with a comprehensive 6-3, 6-2 victory over qualifier Vera Zvonareva. The victory marked a Berlin breakthrough for Sabalenka, who had lost her opening match in each of her two previous appearances at the tournament. 

Current World No.2 Sabalenka needed just 66 minutes to defeat former World No.2 Zvonareva, the 2010 Wimbledon runner-up. Sabalenka extended her undefeated record against Zvonareva to 3-0 after their first grass-court meeting.

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Sabalenka cracked 27 winners in the encounter, well outpacing Zvonareva's three. Sabalenka also converted three of her nine break points in the match, while never facing a single break point on her own service.

Despite her main-draw loss, 38-year-old Zvonareva, a two-time Grand Slam singles finalist, earned her first singles match-wins of the year by beating Nigina Abduraimova and Eugenie Bouchard in this week's qualifying rounds.

In the second round, Sabalenka will face either last week's 's-Hertogenbosch runner-up Veronika Kudermetova or last season's WTA Newcomer of the Year Zheng Qinwen.

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In the last match of the day on Steffi Graf Stadion, Gauff defeated Katerina Siniakova 6-3, 6-4 in 1 hour and 15 minutes. Gauff has now won five of her six singles meetings with 54th-ranked Siniakova.

Highlights: Gauff def. Siniakova

Gauff never dropped serve in the encounter, successfully fending off the lone break point she faced all day. Both players made 16 forays to the net, with Gauff winning 11 of those attempts while Siniakova, the WTA Doubles World No.1, won eight of her approaches.

Gauff is up to 4-1 in her two appearances at the bett1open. The American reached the semifinals on debut last year, beating then-No.7 Karolina Pliskova in the quarterfinals before losing to eventual champion Ons Jabeur.

Gauff has a tricky second-round match lined up against last week's 's-Hertogenbosch champion Ekaterina Alexandrova. In their only previous meeting, Gauff needed a third-set tiebreak to beat Alexandrova at 2021 Dubai.

World No.22 Alexandrova's winning streak is up to six straight matches after she beat 15th-ranked Liudmila Samsonova 6-4, 6-3 in a first-round clash on Tuesday.