Harmony Tan, ranked No. 115 in the world, and Katie Boulter, who is 118th, continue to make names for themselves at Wimbledon, reaching the third round of the women's draw on Thursday with upset victories.
France's Tan, who ousted seven-time Wimbledon champion Serena Williams in a first-round match that lasted more than three hours on Tuesday, rolled to a 6-3, 6-4 victory over 32nd-seeded Sara Sorribes Tormo on Thursday.
Boulter, a British wild-card entry, rallied to eliminate sixth-seeded Karolina Pliskova, who reached the Wimbledon final last year, with a 3-6, 7-6 (4), 6-4 victory on Centre Court.
The road for Tan or Boulder will end in the fourth round, when they are scheduled to face each other.
The 25-year-old Boulter, who reached the third round at a Grand Slam event for the first time, also beat Pliskova last week at a warm-up tournament in Eastbourne for her first win against a top-10 player. She broke Pliskova for a 5-4 lead in the final set, then converted her first match point with a volley winner.
Pliskova's powerful serve looked far from its best throughout Thursday's match, as she mixed 13 aces with eight double faults and was broken four times. She lost last year's final to Ashleigh Barty.
Kvitova was leading 5-1 in the second set when Bogdan started to reel off game after game. Then Kvitova had a match point while serving at 5-4, but failed to convert that chance and then the game itself, eventually leading to the tiebreaker.
"Especially a few games on my serve, it was really long games, and mentally very tough," said the 25th-seeded Kvitova, who won titles at the All England Club in 2011 and 2014. "I think maybe even this took some energy from my serve and I just couldn't make it.
"Somehow I made it," Kvitova said on court. "I don't know how, but I did it."
The Associated Press contributed to this report.