Rennae Stubbs has urged Iga Swiatek to make a critical change if she wants to defeat Jelena Ostapenko.
The Latvian continued her undefeated streak against the World number two at the Stuttgart Open on Saturday.
Ostapenko claimed a 6-3, 2-6, 6-2 victory to hand Swiatek just her second loss at the WTA 500 event in Germany.
Iga Swiatek has failed to win in any of her six meetings against Ostapenko, and for all her success the 27-year-old continues to be her tennis kryptonite.

What does Renane Stubbs think Iga Swiatek needs to change when she plays Jelena Ostapenko?
Swiatek’s Stuttgart Open clash against Jelena Ostapenko was a closer affair than her 3-6, 1–6 loss in Qatar this past February.
After levelling the match at a set apiece, it appeared as though things could change for the Pole and secure a comeback victory.
But Ostapenko had other ideas and continued playing her fearless and aggressive style of tennis to complete victory.
Discussing Swiatek’s struggles on her podcast, Rennae Stubbs has encouraged the Pole to change her serve if she wants to defeat Swiatek.
“If there was a clay court for her not to play her on it would be this one [because it was so slippery],” Stubbs said. “So that’s why it wasn’t that big of a shock that Iga did lose to her on clay, even though she is now 0-6. It is starting to be a little more mental but also it’s that surface, that clay court, did not suit Iga.
“The serve is important. The biggest issue for me, if we go back before Ostapenko beating Sabalenka, is that the serve is so vulnerable. I will talk about it when it comes to players like Iga and Coco. The serve is so important.
“Iga hits the same serve almost every time on the second serve. It’s that kick serve that goes right into Ostapenko’s best shot, her backhand. It is deadly on the returns. Iga has got to figure out a way to get more first serves into court. Her service motion is so discombobulated, there is no fluidity to it.
“When she hits it well, she hits it really well. But you have got to serve well against Ostapenko because if you don’t she is crushing returns on you and she can serve you off the court as well, because indoors particularly, Ostapenko serves well.”

Rennae Stubbs explains how Jelena Ostapenko causes Iga Swiatek problems
Ostapenko’s win over Swiatek in Stuttgart now means she has defeated the reigning French Open champion on grass, clay and hard courts.
Three of those victories have come in straight sets, and her front foot style of play has caused Swiatek plenty of problems throughout their rivalry.
Stubbs thinks this is due to Ostpenko’s second serve returns and ability to force Swiatek to defend, which the Australian thinks is an area of weakness for Swiatek.
“Ostapenko knows that she is going to take advantage of the second serves, that’s for one,” Stubbs said. “She knows that if Iga is not controlling the point she is not a great defender, particularly on the forehand side.
“So Ostapenko uses her flat ball striking and aggressive play – and also Ostapenko, and I have coached against her a bunch of times, she is a player you go what are her strengths and weaknesses and where does she go under pressure.
“I want to see Iga start producing a little bit of variety when she plays against her. I didn’t see one drop shot. One attempting real slice.
“It is not easy to do that against Ostapenko because she is hitting the ball so hard and flat, but there were times where I felt she could have done a drop shot, hit a bit of a different shot and she chose not to.
“Slice the ball short, drop shot once in your life in a match, because when you become predictable, that is predictable for them to be able to read what you are doing. And Iga made some really bad, bad choices of shot and bad errors in the the set, particularly off the return.”
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