NEW HAVEN, Conn. (AP) Two-time defending champion Petra Kvitova needed just an hour Thursday to beat Ekaterina Makarova 6-3, 6-1 and move into the semifinals of the Connecticut Open, despite suffering from a cold.

Looking to join Venus Williams and Caroline Wozniacki as a four-time winner in the tournament, Kvitova overpowered the Olympic doubles champion, breaking her four times - three during the 25-minute final set.

''I think that sometimes I can't really pay too much attention how I feel,'' Kvitova said. ''It's just going out there, just being strong mentally, think about the next point, think about the tennis.''

The Olympic bronze medalist and two-time Wimbledon champion has been criticized during her career for inconsistent play. But the Czech star will be looking for her fifth consecutive appearance in the finals here and her third straight title. She also won in 2012.

''They should look at New Haven,'' she said about her critics. ''It's always nice to coming somewhere when you feel, you know, at a home and you know you can play well. It always gives you little bit more confidence than normally.''

She will face top-seed Agnieszka Radwanska of Poland in the semifinals. Radwanska beat lucky loser Kirstin Flipkens of Belgium 6-1, 6-4.

The world's fourth-ranked player had an easy time in the first set, but needed a break in the ninth game of the second set to secure the win over the 30-year-old Flipkens, who struggled with an injury to her left hand.

Flipkens, who upset Venus Williams at the Olympics, had lost in the second round of qualifying in New Haven. But she was moved into the main draw after Lesia Tsurenko withdrew with a right knee injury, then beat Belinda Bencic and Caroline Garcia.

Ukraine's Elina Svitolina advanced with a 6-3, 6-1 victory over Elena Vesnina, Makarova's double's partner in Rio. Svitolina outran her Russian opponent and took advantage of 33 unforced errors.

''I was trying to push her to make those errors,'' she said. ''I think in the end she was just going for too much.''

The 21-year-old Svitolina will play Johanna Larsson, the 28-year-old Swede who upset second-seeded Roberta Vinci of Italy 7-6 (9), 6-1. Larsson lost in qualifying, but got into the main draw when Svetlana Kuznetsova withdrew because of a shoulder injury.

Larsson is the third lucky loser to advance to the semifinals in New Haven, joining Samantha Stosur (2006) and Tsurenko (2015).

Vinci said she was bothered by an injury to a tendon in her left foot that has been giving her problems since the Olympics.

''I was thinking always to my pain, and I lost,'' Vinci said. ''But now I have two or three days off before New York to try to recover.''