Petra Kvitova and Angelique Kerber, both winners of multiple Grand Slam titles, triumphed in their first-round encounters over qualifiers at the inaugural Bad Homburg Open presented by Engel & Völkers on Monday.

No.1 seed Kvitova, as it turned out, had her hands very much full in her match before outlasting Katarzyna Piter of Poland, 4-6, 6-1, 6-4. The Czech needed nearly two hours to quash the challenge by the former Top 100 player, including fighting back from an early break down in the final set.

Former World No.2 Kvitova was playing her first match since suffering an ankle injury three weeks ago, following her first-round win at Roland Garros. Kvitova slammed ten aces in her comeback contest, but had to survive three breaks of her service before squeaking through to the second round on the German grass.

"I felt kind of a mix of emotions," Kvitova said, after her win. "I was pretty happy to be back on the grass. On the other hand, I thought I was probably going to play a little bit better. It was my third hit after my injury, so I probably expected a little bit more from myself than I really showed today."

"In the end I won, so that's a pretty good result," Kvitova added. "I found a few games where I really played good grass tennis, and that's what I will have to take with me."

Two-time Wimbledon champion Kvitova received a stern test right away from World No.387 Piter, who was playing in her first WTA main draw since 2018. Piter used a lob winner to set up a break point at 3-3, and after she won that game to take the lead, she moved through the rest of the set without facing another break point.

Kvitova bounced back tremendously, using her powerful game to race through the second set without turmoil. Yet Piter continued to press the Czech, and the Polish player drew a clutch of forehand errors from Kvitova to take an early 2-0 lead in the decisive third set.

Kvitova, though, broke Piter three times in the next five games to edge ahead by 4-3, and the Czech slid to match point at 5-3. Piter got through that game with some deft reflexes at net to hold, and Kvitova nearly faltered after hitting double faults on her next two match points at 5-4.

But on Kvitova's fourth match point, she hit her tenth ace to close out the clash, sending the Czech into the second round, where she will face Ann Li of the United States. Li also defeated a qualifier on Monday, dispatching Germany's Anna Zaja, 6-0, 6-4.

No.4 seed Kerber had a much easier time on Monday, as she defeated Russia's Ekaterina Yashina, 6-1, 6-1 in under an hour on home soil.

"Of course, it's a great feeling to win the first match, especially here in Bad Homburg, which is a really special tournament for me," Kerber said, after her victory. "To play in front of the home crowd, it's always something I'm looking forward to and really excited [about]."

Former World No.1 Kerber looked strong on the grass, the surface on which she won the third of her three Grand Slam titles, at 2018 Wimbledon. Kerber won nearly three-quarters of her first-service points and went 9-for-10 winning points off of Yashina's second serve.

"It was a good win for me, and I was feeling really well on the center court tonight," Kerber said.

After a passing winner to break for 2-0, Kerber faced three break points in the next game, but she pulled herself out of danger, finishing off that game with a forehand winner to reach 3-0. After extricating herself from that jam, Kerber never faced a break point for the rest of the day.

A backhand winner gave Kerber a second break to lead 5-1, and another winner off of that side cued up the German's first set point, which she converted with a rally-ending volley.

The second set was just as comprehensive as the opening frame, with Kerber reeling off the first four games before World No.478 Yashina, who was making her tour-level main-draw debut, could get on the scoreboard.

Kerber used a forehand winner to wrap up the match, setting up a second-round battle with Anna Blinkova of Russia. Blinkova defeated Danish teenager Clara Tauson 7-6(4), 4-6, 6-2, earlier on Monday.

Siegemund survives scare from surging lucky loser Bhatia: Bad Homburg Highlights

2021 Birmingham

Another German, No.8 seed Laura Siegemund, had to fight past a lucky loser to book her spot in the second round in her home country. World No.55 Siegemund needed just over two hours to eke past India's Riya Bhatia, 2-6, 7-6(2), 6-1.

World No.362 Bhatia twice led by a set and a break in her tour-level main-draw debut, before Siegemund surged back to zip through the second-set tiebreak and eventually claim the win.

But No.3 seed Jessica Pegula of the United States had no such problems defeating 264th-ranked Amandine Hesse of France, 6-1, 6-2, in 65 minutes.

Rounding out Monday's first-round results, Alizé Cornet of France defeated Arantxa Rus of the Netherlands, 6-3, 2-6, 6-1, and No.7 seed Sara Sorribes Tormo of Spain beat Martina Trevisan of Italy, 6-4, 3-6, 6-2.