A host of upsets opened Day 3 at the Rothesay International, with four seeds falling in the second round after receiving byes.

Marta Kostyuk returned to complete a 4-6, 6-3, 6-4 loss to No.7 Barbora Krejcikova, a match that had been delayed due to darkness in a set all day previous; and wildcard Katie Boulter delighted the home crowd with a 1-6, 6-4, 6-4 comeback against No. 4 Karolina Pliskova.

Elsewhere, Kirsten Flipkens continued to find form on her farewell tour. The Belgian, who will retire from singles competition after Wimbledon, knocked out compatriot and No. 13 seed Elise Mertens 6-2, 2-6, 6-1 for her first Top 30 win since Moscow 2019 Flipkens’ fellow qualifier Lesia Tsurenko completed a quartet of upsets, beating No.9 seed Elena Rybakina 1-6, 7-5, 6-3 to claim her first Top 25 win since Brisbane 2019 .

Highlights: Flipkens d. mertens

How Kostyuk upset Krejcikova: Kostyuk, 19, ranked No. 79, played with the usual panache from the start, opting for bold, low-percentage winners down the line early in the rallies. However, for a set and a half, it was Krejcikova’s more controlled play that had the upper hand.

The Czech had been sidelined for three months this year with an elbow injury, only returning to Roland Garros – where her title defense ended in the first round against Diane Parry, and where she suffered another setback in the form of Covid. But leading 6-4, 3-4, she had yet to drop a serve and had indeed only faced one break point.

But Kostyuk finally caught Krejcikova’s serve after five points to lead 5-3, and went from that point on getting stronger. At 4-4 in the third set, perhaps the best play of the game was also Kostyuk’s after a fight to several draws, as the Ukrainian found a wonderful pass to take her fifth break point of the game . She also found more flair to convert her second match point by lobbing over Krejcikova’s head.

The result was Kostyuk’s second win in as many encounters with Krejcikova, having also won 6-3, 5-7, 6-0 in Australian Open 2018 qualifying. It was also the Kostyuk’s second victory in the Top 20, after his upset against GarbiƱe Muguruza at Roland Garros last year.

How Boulter upset Pliskova: After a first set characterized by missed chances and 11 unforced errors, Boulter’s chances of claiming the first Top 10 of his career looked slim. The Briton wasted nine game points – seven on Pliskova’s serve and two on herself – in the first five games of the match to lose 5-0.

Indeed, Boulter would be unable to convert the first 13 break points she held on Pliskova. The Czech, two-time Eastbourne champion in 2017 and 2019, repeatedly got out of dangerous situations with solid first serves.

But after one of the many dead net cords brought a 14th break point for Boulter at 4-3 in the second set, Pliskova finally offered a second serve and then scored a backhand. It was the start of a rushing dive as his forehand and serve started to give up on him.

The second game of the third set featured four consecutive double faults by Pliskova; and although she managed to equalize at 2-2, she could not find the form needed to regain Boulter’s momentum. Pliskova eventually tallied 40 unforced errors and 11 double faults; Boulter, ranked No. 127, found 26 winners for 34 unforced errors and capped the victory with a fifth break of serve from Pliskova.