Welcome back 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. After recapping Charleston's classics, our retrospective now heads to Stuttgart, Germany to recount some of the best matches from recent editions of the Porsche Tennis Grand Prix. Next up is the epic between big-hitters Karolina Pliskova and Jelena Ostapenko that closed out the 2018 quarterfinals.

Stuttgart Rewind:
2015: Angelique Kerber d. Maria Sharapova, second round
2016: Petra Kvitova d. Garbiñe Muguruza, quarterfinal
2017: Laura Siegemund d. Kristina Mladenovic, final

HOW THEY GOT HERE: A look at Karolina Pliskova's rise to the top tier of women's tennis would primarily show success on hardcourts, yet her less-talked-of clay court results have been arguably as essential. Winner of the 2016 Western & Southern Open and runner-up at the US Open three weeks later, Pliskova couldn't have ascended to World No.1 without a semifinal finish at Roland Garros the following spring.

"Everyone was just saying that I cannot really play good on clay," she mused back in 2017. "But I feel in future and in my clay future this was definitely a positive thing."

That fortnight ended with a narrow loss to Simona Halep, and gave Pliskova plenty of incentive to start the 2018 clay court season with a positive mind-set, promising the press as much at the Miami Open.

"I think I was joking at that time," she laughed after a second round win in Stuttgart. "But, no, I'm trying to take it in a little bit different way than I was taking it the last two years."

The slower surface may blunt the four-time WTA Ace Leader's most powerful weapon, but the higher bounce clay provides gives Pliskova time to set up her metronomic swings and brought her through a pair of straight set wins over Kiki Bertens - who was on the precipice of her own breakout results - and Veronika Kudermetova.

Awaiting her in the last eight was reigning French Open champion Jelena Ostapenko, who defeated Pliskova's conqueror Halep for a stunning Grand Slam triumph nearly a year prior. 

First famed for her junior Wimbledon title, the Latvian's wild party in Paris was a testament to how dangerous her game can be, regardless of surface, opponent, or sometimes unreliable serve. It soon translated to a quarterfinal at the All England Club and a first WTA title on hardcourts in Seoul.

Her topsy-turvy results were seemingly trending back upward at just the right time; with her title defense just two months away, she surged into her first Premier Mandatory final in Miami, and won her first clay court match of the year in emphatic style over Zarina Diyas - dropping just three games.

The rivals had played thrice before, with the Former World No.1 winning the first two - including a 10-8 final set at the 2017 Australian Open - while Ostapenko ended her WTA Finals debut with a decisive round robin win over a Pliskova who had already qualified for the semifinals.

2018 Stuttgart Highlights: Karolina Pliskova rallies past Jelena Ostapenko

WHAT HAPPENED: Ostapenko was on fire out of the gate, losing just one point on serve to take a 3-0 lead. Pliskova swiftly leveled in kind but couldn't get on top of another return game as the Latvian dug out of two break points - one with a powerful backhand putaway - to move within a game of the set.

That backhand continued to serve Ostapenko well, thundering a cross-court return into the corner to take the opening set, and the No.4 seed parlayed that momentum into two more confident service games to start the second set.

Match Report: Pliskova outguns Ostapenko for maiden Stuttgart SF

Pliskova continued to press, and shook off an exchange of breaks to keep things close as the pair approached five games apiece. Securing the critical break, Pliskova flew to net on set point, smacking a forehand into the open court to force a decider.

The final set played out similarly to the second: Pliskova thundered a backhand up the line to break first, and remained in front even as Ostapenko repeatedly threatened to draw level.

She made her last stand as Pliskova served for the match, engineering three break points that ultimately went begging as the Ace Queen sealed it with a service winner.

WHAT THEY SAID: The long night wasn't over for Pliskova, who took to post-match press to break down the clash in her signature staccato.

"I think she was returning pretty well today and just playing one of the best matches I played with her," she explained, never one to give idle compliments. "I know she can play well, she can play this way, but she can also give you some points, which happened in the second and third sets where she had about two games where she was a little bit off.

"I didn’t think I played that bad in the beginning, but she just started like very well, hitting the ball pretty deep, so there was not much to do. She can play this way. So, I was just waiting for the chances. I got few every set. On some points she played well, then she gives some mistakes. I think it was from here a little bit up and down and I was just holding my level, waiting for the chances and I got it."

Praised for her improved defense, Pliskova - ever the perfectionist - called it crucial to her clay court success.

"I did a lot of work with my sliding on the clay. So, I’m just happy that I could show it today. I know my slices are pretty good, especially the ones from the forehand side, so I try to use it. I think it’s sometimes a good change of the rhythm, especially against the players which are hitting like this. It is sometimes good to mix the speed, to change it a little bit.

"But obviously, it's not my style and I don’t want to really wait for a mistake of the opponent. Sometimes it's necessary and there is no other chance what to do."

WHAT IT MEANT: Pliskova would mix offense and defense all the way to the title that week in Stuttgart, overcoming challenges from Anett Kontaveit and CoCo Vandeweghe to capture her first Premier title on the terre battue. Later that swing, she scored an impressive victory over Simona Halep at the Mutua Madrid Open, snapping the Romanian's 15-match winning streak at that event while extending her own clay court streak to nine in a row.

The following season saw further improvements on clay, culminating in a Premier 5 crown at the Internazionali BNL d'Italia, her biggest title since winning Cincinnati in 2016.

Ostapenko maintained her momentum through the spring, reaching the quarterfinals in Rome - pushing Maria Sharapova through three dramatic sets - and though she fell in the first round of Roland Garros, roared into the Wimbledon semifinals, falling to eventual champion Angelique Kerber.

While injuries and inconsistency caused the youngster to regress, the Latvian showed signs of life at the end of 2019 with new coach and 2013 Wimbledon champion Marion Bartoli, reaching back-to-back finals in Linz and Luxembourg, winning the latter over Julia Goerges in straight sets.