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. Kicking things off is Angelique Kerber's dramatic second round win over three-time defending champion Maria Sharapova from 2015. 

HOW THEY GOT THERE: Having won her first clay court title a fortnight earlier in Charleston, Angelique Kerber returned home to the 2015 Porsche Tennis Grand Prix riding a wave of momentum.

Despite having dropped out of the Top 10 for the first time in three years in the early spring, Kerber started rolling when she hit the clay courts. To begin the clay season, she won her first WTA title since 2013 on the green clay of South Carolina with five wins in a row, and added a sixth consecutive victory to her ledger with a 6-1, 6-0 win over Anastasia Pavlyuchenkova in the Fed Cup semifinals on Sochi's red clay.

Charleston rewind: Kerber unlocks Keys for first clay title

In Stuttgart, a 6-2, 7-5 win over American lucky loser Alexa Glatch in the opening round sent the unseeded German into a second round clash with top seed and three-time defending champion Sharapova, who was already the first player to win consecutive titles at the event since its move from Filderstadt to Stuttgart in 2006. 

Sharapova won 10 straight matches to start 2015 with a runs to the Brisbane title and Australian Open final, but arrived in Stuttgart having not not played in nearly a month after losing in the second round of the Miami Open to Daria Gavrilova, her earliest exit at that tournament since 2006. 

With Kerber looking to make the quarterfinals in Stuttgart for the third time since her main draw debut in 2012, something had to give: either Kerber would extend her season-best winning streak on clay, or Sharapova would keep an undefeated record in Stuttgart in tact.

"I’m looking forward to playing against Maria," Kerber said ahead of the match. "We've had very tough battles in the past. It’s always nice to play against her and I will give my best. 

"I played very well in the last few weeks and I have a lot of confidence. I think I’m ready, I’ve had great matches in the last few weeks and I will just go out there and try to enjoy and play very good tennis against her."

WHAT HAPPENED: Despite having not played a competitive match for nearly a month, it was a dominant start for Sharapova in the fifth meeting all-time between the two players, and their second in Stuttgart.

Sharapova had previously earned a 6-3, 2-6, 7-5 semifinal victory en route to winning the 2013 title, and the Russian won six of seven games - including four straight to win the set from 2-2 - after losing serve to start the match to wrap up a the first set of the 2015 encounter. 

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The five-time Grand Slam champion kept her lead deep into the second set, as she continued to hold serve for much of it under little threat.

Neither player faced a break point until Kerber saved what was ultimately the lone chance for either player over the first 10 games in a hold for 3-3, and she later earned the decisive break from another deficit.

Unable to convert a 40-15 lead on serve at 5-5, Sharapova dropped the next four points to trail for the first time since 1-0 in the opening set, before the unseeded Kerber wrapped up the set and sent the match to a decider. 

The German's momentum carried her into the final set, and she proved strong in the face of adversity: after being pegged even at 1-1 after breaking serve in the opening game, Kerber responded with an crucial break that gave her a lead she'd never relinquish.

Again, from 40-15 down, Kerber battled to earn herself break points, and sealed the first of five consecutive games on her fourth opportunity to lead 2-1. 

Sharapova earned just one chance to break in Kerber's last two service games - an opportunity for 2-2 - but never held serve in the final set to help Kerber earn a 2-6, 7-5, 6-1 victory.

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WHAT THEY SAID: Following the match, both players were complementary of the level of tennis in a match that lasted just about two-and-a-half hours -- but the German expressed that she felt the difference-maker was something outside the court. 

"We both played very good, top, high-level tennis actually," Kerber said in victory. "I was trying to go for it in important moments. In the second set, when it was 5-5, I was trying to go for it. 

"I was a little bit tired also in the second set, but when I heard the crowd, I was fighting until the last point. It was an amazing feeling to play, and the support from all of the great fans here at home.

"I was fighting until the last point and I’m just happy to beat Maria here. It’s a special moment and also a special tournament for me. To play at home and in front of my family and friends, it’s just a great feeling."

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"Matches can change any time, really," Sharapova reflected in defeat. "I’ve been in many different situations and circumstances where, no matter if you’re leading, you’re behind, it’s never over until the last point.

"You have to expect her to be the crowd favorite in the match. I absolutely respect that. I just wasn’t aggressive enough. And with that she gains a little bit of confidence, makes a few shots, guesses right and then all of a sudden, you are in a bit of a fight.

"She was moving very well and was retrieving so many volleys, so I had to open up the court a little bit more and maybe the lines were something I could have done better, but she played really well. I have to give it to her."

WHAT IT MEANT: Kerber's victory snapped Sharapova's staggering 13-match winning streak in Stuttgart, making her the first player to ever beat Sharapova at the event and denying her a chance to win an unprecedented fourth consecutive title.

Ultimately, however, the victory also allowed Kerber to make her own history: by the end of the week, the German went on to win her first Stuttgart title, beating No.6 seed Ekaterina Makarova, Madison Brengle and No.4 seed Caroline Wozniacki in the last three rounds.

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The second German to win the title in Stuttgart's Porsche Arena after Julia Goerges in 2011, Kerber successfully defended her title one year later against compatriot Laura Siegemund, who went on to win her own Porsche in 2017 in a stretch of unprecedented success for home players at the Premier-level event.