NOTTINGHAM, UK - Four days into the Nature Valley Open, No.2 seed Donna Vekic finally got her feet on her beloved grass - but although that lasted under a set in total, the former winner survived a long afternoon of rain delays and, eventually, a move indoors to defeat No.8 seed Kristina Mladenovic 7-5, 6-4 and reach her third straight semifinal in Nottingham.

"I’m just happy the match is finished, I won, and I'm going back to the hotel now," Vekic said with a laugh, after her victory. "It’s just been a really crazy day."

The 2017 champion had never beaten Mladenovic before this year, having lost two previous encounters in Madrid and Baku in 2014, but has now leveled the head-to-head at 2-2 thanks to today's result and a 6-2, 6-4 first-round victory at the Australian Open in January. Striking 18 winners to only 13 unforced errors in total, Vekic displayed canny shot selection in adjusting to trying conditions that involved four separate rain delays before the first set had been completed and a switch to Nottingham's indoor facilities just as the Croat was about to serve for the first set.

"Everything was working again today," Vekic continued. "But it was just [about] trying to adapt from playing outside on the grass, the raining, the court is a little bit wet, and then coming fast indoors, where [Mladenovic] completely changed her tactics indoors as well."

"Thankfully I adapted quickly and was able to finish in two sets," Vekic concluded.

Vekic, currently perched at a career-high ranking of World No.22, was the quicker to settle, contributing a booming backhand winner down the line as Mladenovic struggled to find her range on that wing to get broken in the opening game. She was able to maintain that lead through two short pauses for rain at 2-1 and 4-2 - but matters got more complicated when Vekic stepped up to serve for the set at 5-4, with the 22-year-old offering up four unforced errors out of nowhere to get broken back.

Ultimately, though, it was Vekic who demonstrated superior composure as rain began to edge, unwanted, into the spotlight once again. One point later, heavier precipitation forced the players off court for over an hour; in a resumption that lasted only five more points, Vekic took full advantage of the damp conditions to regain her break, cannily utilizing the dropshot to carve out her opportunity.

Similarly, despite being forced to serve out the set after another hour-plus break and on a different surface as tournament organizers opted to move play indoors once more, Vekic rose to the occasion with clutch serving and emphatic forehand putaways to seal the set.

The St Petersburg runner-up remained sharp as the second set got under way, breaking Mladenovic in the third game by reading a dropshot perfectly and tapping a pass past the Frenchwoman - and then on the next point essaying a dropshot of her own to set up another pass.

Once Mladenovic had found her groove indoors, the newly crowned doubles World No.1 was able to bring some of her characteristic panache in the forecourt to the contest, battling through two tight service holds to avoid the double break - and then constructing a brilliant point that finished with an elegantly angled volley to set up break-back point for 4-4, taken when Vekic sent a backhand wide.

But the 26-year-old's form, though scintillating at times, had been rather more intermittent than Vekic, whose flashy aggression - particularly on the backhand down the line, which contributed a flow of winners to proceedings - was backed up by greater stability in rallies and on a point-to-point basis. Mladenovic would lose serve again immediately with another sequence of mistakes - her unforced error tally would eventually reach 22, in addition to five double faults.

Serving for the match, Vekic made no mistake, fighting through a brace of compelling all-court exchanges before sealing victory after one hour and 46 minutes on court on her first match point with a judiciously timed dropshot. No.9 seed Tatjana Maria awaits in the semifinals; the German mother-of-one was triumphant in the only match to be completed on grass thus far this week, displaying smart courtcraft to out-slice No.6 seed Ajla Tomljanovic 6-3, 7-6(7) in the day's first quarterfinal.

"Hopefully the weather’s looking a little bit better," Vekic said, looking forward to Saturday's semifinals. "I’m hoping we’re going to play outside."