Welcome to Clay Chronicles, where wtatennis.com will take a look back at some of the most memorable matches from the clay seasons of the past five years. Up next from Charleston is a hard-hitting 2018 semifinal marathon between Kiki Bertens and 2015 finalist Madison Keys, where the Dutchwoman blasted to a whisker-thin win en route to her maiden Premier-level final and title.

Charleston Rewind:
2015: Angelique Kerber def. Madison Keys, final
2016: Sloane Stephens def. Daria Kasatkina, quarterfinal
2017: Jelena Ostapenko def. Mirjana Lucic-Baroni, semifinal

HOW THEY GOT HERE: A breakthrough run to the Roland Garros semifinals in 2016 was all it took for the tennis world to take a new look at Kiki Bertens as a clay-court force. That fortnight, the Dutchwoman upset No.3 seed Angelique Kerber -- who had won the previous Grand Slam event -- in the first round, then notched wins over No.15 seed Madison Keys and No.8 seed Timea Bacsinszky before falling to World No.1 Serena Williams in a closely contested semifinal.

Suddenly, the Dutchwoman had rejuvenated her singles career, as she slid into the Top 30 for the first time in her career. Armed with a massive serve and a heavy forehand, Bertens became one of the most dangerous players on tour, and her powerful game led to success on all surfaces, but particularly on clay.

Bertens picked up three clay-court titles during 2016-2017, as she solidified her spot in the upper half of the Top 100 within that timeframe. However, coming into the 2018 Volvo Car Open, Bertens had yet to reach a Premier-level final, despite having collected four WTA singles titles in her career at International level (all on clay).

Bertens put herself one match away from breaking that duck by moving into the 2018 Charleston semifinals. Seeded 12th, Bertens had surged into the final four without dropping a set in her four matches, sealing that spot with a quarterfinal victory over No.14 seed Alize Cornet of France, and setting up another showdown with Keys.

"The clay is helping me a little bit, like with my forehand and with my heavy strokes, but I guess it's more mentally," Bertens said after her win over Cornet. "My level is maybe 20 percent better, but in my head I feel like I'm 80 percent better."

Meanwhile, at this point in time, Keys had reached seven WTA singles finals, winning three titles, but unlike Bertens, all of the American's finals had come at Premier-level or higher events, including a runner-up showing at the 2017 US Open.

Moreover, Keys had posted a couple of strong results at the Volvo Car Open, reaching the quarterfinals in her 2013 main-draw debut at Charleston, then reaching the final in 2015, where she lost an incredibly tight battle with Kerber.

Keys, though, was on a mission to hoist the trophy which had eluded her three years prior. The former finalist had fought back from a break down in the final set to win her quarterfinal match against fellow American Bernarda Pera, moving into her first semifinal of the season, and now had a chance to avenge her 2016 Roland Garros loss to Bertens, which was the only previous meeting between the combatants.

"I always feel the crowd support when I'm out here, and I definitely appreciate it," said Keys after her quarterfinal comeback.

Photo by Volvo Car Open Facebook

WHAT HAPPENED: All four semifinalists were staring down a packed championship Sunday. The day before, torrential rain forced the first semifinal between Julia Goerges and Anastasija Sevastova to be suspended at 4-4 in the opening set, and the precipitation never abated on Saturday, pushing the remainder of the schedule to the next day.

Now first up in the morning, Bertens and Keys faced off knowing that the winner would have to come back to contend for the title later in the afternoon. Even with that task looming in the future, both players fought tooth and nail to come out on top in what would turn out to be an epic encounter.

After three consecutive breaks of service to open the match, Bertens ended that streak by holding for 3-1 after fending off three break points in that game. Breaks were exchanged later in the set as Bertens gritted her way to a 6-4 lead, after an opening set where Keys was undone by 24 unforced errors.

Keys then let a 5-3 lead slip in the second set, as Bertens reeled off three straight games to reach 6-5 and serve for the match. Bertens held two match points in that game for a routine two-set win, but the aggressive mindset of the American suddenly roared to the fore, as she blasted two winners to erase those chances. Keys went on to break for 6-6, and the former finalist, now revitalized, cruised through the second-set tiebreak.

An electric decider began with no breaks of serve through 4-4, but Keys was the first to break through in that game, going up 5-4 and serving for the match. Keys held a match point in that game, but netted a rally forehand to miss her opportunity, and Bertens summoned her strength to clinch her first break of the set, and get level at 5-5.

Keys crushed more forehands to break Bertens again at 6-5, giving herself a second chance to serve out the victory. But Bertens came through in the clutch once more, slamming an overhead on break point to send the bruising tilt into a decisive final-set tiebreak.

The duo stayed within touching distance of each other deep into the breaker, but Bertens used sturdy crosscourt forehands to her benefit, drawing errors from the American. At 6-5, the Dutchwoman was the first to hold a match point in the tiebreak, which came an hour after her two previous match points. That chance was converted, and Bertens grasped the 6-4, 6-7(2), 7-6(5) win after a grueling two hours and 42 minutes, moving into her first-ever Premier-level final in the process.

WHAT THEY SAID: "I was just like so happy that I could finish that match with the win," Bertens told the press. "Also on court I was already thinking like 'Oh, if I win I have to play another match.' But I was just not focusing about that, just trying to get the win. And it gives you so much energy."

"It was a really tough match," Bertens continued. "I think it was good tennis. It was tough because when we started it was really cold, so it was really different conditions than the rest of the week. But we both had to deal with that. 

"And I think I was playing a good match. And then [I got] a little bit nervous to close it out in the second set, and there you are in the third set. And I was just, keep on going, keep on fighting, even when I was match point down."

Keys was reflective and optimistic after the marathon match. "It's definitely something I can build off of," the American said to the media. "You know, it's a good solid week, first one I've had since Australia, so looking to keep working on that. And I'm going to Fed Cup. So hopefully I can have these good matches going go into that."

"it's one of those things where I know I can play on clay," Keys added. "It's just taking a deep breath, mostly. I'm actually really excited to go to Europe this year and play on clay. You know, it's always really nice to have a good solid week at the start of it. And [I'm going to] Fed Cup and I'm going to play Stuttgart. So I've added some tournaments, and hopefully this is the year that I say that I love it."

Photo by Volvo Car Open Facebook

WHAT IT MEANT: If Bertens had been winded after attaining that whisker-thin win over Keys, she didn't show it in the final later that day. The Dutchwoman cruised to victory over No.5 seed Goerges, 6-2, 6-1, after just 58 minutes of play, claiming the biggest WTA singles title of her career up to that point in the process.

"It's just unbelievable," Bertens told the press, following her championship victory over Goerges. "I think I cannot really realize it yet, but I'm just so happy and proud I think of myself. It's a great start of the clay court season, and hopefully still more to come, but this one I have already and I'm really happy with that."

With a Premier title at last under her belt, Bertens used her Charleston run as an impetus to put together a tremendous season. Bertens continued her success on clay by reaching the final in Madrid, then claimed her first-ever Premier 5 title on the hardcourts of Cincinnati during the summer. Another hardcourt title followed in Seoul, and by the end of the season, Bertens had made her Top 10 debut and clinched a precious singles spot at the year-ending WTA Finals for the first time.

Despite another close loss at a tournament she holds dear, Keys also kept her season on an upward trajectory. Her excitement to play on the European clay-courts led to a career-best showing at Roland Garros, where she reached the semifinals before falling to good friend Sloane Stephens. In the summer, she reached her second Grand Slam semifinal of the season at the US Open, ultimately being stopped by eventual champion Naomi Osaka.

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