No.5 seed Belinda Bencic survived a difficult opening test at the inaugural bett1 Open on Monday, outlasting German qualifier Jule Niemeier 4-6, 6-4, 7-5.

"She’s a great opponent," Bencic said on court after her win. "I knew she was capable of great tennis, and she’s playing her best tennis right now, so I was expecting a tough match."

Bencic, the World No.12, needed two hours and 12 minutes to fend off the challenge from 167th-ranked Niemeier, who was on home soil and playing her first professional grass-court tournament.

Both players were excellent on their first-service points, with Bencic's 80 percent success rate edging Niemeier's 75 percent. Ultimately, the match came down to Bencic having one more service break than Niemeier, which conveniently came in the final game of the clash.

"I tried to fight, I tried to play with what I had, and I’m glad I won," Bencic said.

Niemeier had a rip-roaring start to the match, winning the first eight points. The German qualifier slammed backhand return winners repeatedly as she garnered a 4-1, double-break lead with a love hold. Bencic did claw one break back to pull to 5-4, but Niemeier served out the set in the next game.

Niemeier's early form was reminiscent of her breakthrough semifinal run in Strasbourg last month, where she notched her first career WTA match-wins before falling in three close sets to eventual Roland Garros champion Barbora Krejcikova.

Bencic, though, steeled herself, crucially saving four break points at 2-2, which were Niemeier's only break points of the set. After that, the former Top 5 player served superbly to pick up two routine service games in a row, then broke Niemeier in the final game of the set, tying the match after a backhand passing winner.

In the decisive third set, Niemeier kept level with Bencic after saving three break points en route to a hold for 3-3. From there, the pair moved to 6-5 without facing any additional break points, but a seemingly inevitable tiebreak was quashed when Bencic took charge with strong returns in the final game to break for victory.

Bencic now moves into the second round, where she will face either Petra Martic of Croatia or American qualifier Asia Muhammad.

Bencic survives surging Niemeier's shotmaking: Berlin Highlights

2021 Berlin

Madison Keys of the United States followed with a win in the final match of the day, defeating Polish qualifier Magdalena Frech, 6-3, 6-4.

Keys is eyeing a third WTA singles title on grass this week, as two of her five career titles have come on the surface: 2014 Eastbourne and 2016 Birmingham.

World No.28 Keys fired 19 winners to Frech’s seven as the American fended off a late comeback by 149th-ranked Frech and eased into the second round in one hour and 15 minutes.

Frech broke Keys in the opening game of the clash, but the American got back on track relatively quickly, reaching level footing at 2-2. Keys then moved ahead for good in the opener, claiming a break for 5-3 when a return winner landed square on the baseline on break point. A down-the line forehand winner in the next game closed out the first set for Keys.

Porsche RoadTrip: Belinda Bencic

Keys had all the momentum in the early stages of the second set, knocking off a winning volley to lead by two breaks at 3-0. But with Keys serving for the victory at 5-2, Frech surged. The qualifier saved a match point with a volley winner of her own, then forced an error with a down-the-line backhand to break Keys for 5-3.

Keys, though, would not make the same mistake twice. At 5-4, the American served out the match successfully at love, lining up an eye-catching battle with No.1 seed Aryna Sabalenka in the second round.

"I think [Frech] played a couple of good points in my [second-to-last] service game, and she came out and had another good service game on her side," Keys recalled on court, after her win. "I was happy I made it a little less complicated in the last game."

In earlier first-round matches in Berlin, Alizé Cornet of France defeated Amanda Anisimova of the United States, 6-3, 6-1, in one hour and 14 minutes.

Anisimova had won their sole previous encounter in straight sets, which had also taken place on grass, at 2019 Mallorca. But Cornet was able to level their head-to-head, winning three-quarters of her first-service points and breaking Anisimova five times.

Next up for Cornet will be a battle against No.3 seed Bianca Andreescu in the second round.

Also, Ekaterina Alexandrova took just over an hour to beat wildcard Anna Kalinskaya, 6-3, 6-2, in an all-Russian clash. Alexandrova is now 4-0 against Kalinskaya.

Alexandrova never faced a break point as she eased past her compatriot, setting up a second-round clash with No.2 seed Elina Svitolina.