China's Li Na has said she expects a tough battle in Sunday's final at the Stuttgart WTA clay-court tournament against defending French Open champion Maria Sharapova.
Li, the 2011 Roland Garros winner, takes on Sharapova after the top seeds came through Saturday's semi-finals, but the Russian is unbeaten in Stuttgart having won all seven of her games on her two appearances here.
"Sharapova's a fighter, she never gives up and I will have to focus on every point out on the court," said the 31-year-old Li after Sharapova won last year's final on her Stuttgart debut.
"She's an aggressive player, but every final is tough."
Li won their last meeting in January's Australian Open semi when the Chinese enjoyed a 6-2, 6-2 victory; her fifth win over the Russian, who has beaten her eight times.
Second-seed Li enjoyed a 6-4, 6-3 win over qualifier Bethanie Mattek-Sands of the USA, ranked 104th in the world, to reach the final.
"We both had our chances and it was a very tough match," admitted Li.
"It was a tight match and I was starting to lose energy as the second set wore on and a few 50:50 things went my way, but that's tennis."
With a brand-new Porsche waiting court-side for Sunday's winner to drive off, Li admitted she could be presented with a luxury problem as her sponsorship deal with Mercedes would forbid her from driving her prize.
"I would have two options: keep it in my garage until the contract expires or give it to my husband," she said.
Earlier, Russia's Sharapova saw off Germany's Angelique Kerber in her last four clash with a 6-3, 2-6, 7-5 victory as she was again involved in a marathon tussle.
The 26-year-old Russian has also been taken to three sets in both her previous matches, when she saw off Lucie Safarova, then Ana Ivanovic in Friday's semi, and showed some grit to see off Kerber, who was cheered on by the crowd.
Sharapova, the world number two, has played seven-and-a-half hours in her three matches here on clay, but comfortably took the first set with two breaks, before Kerber returned the compliment in the second.
The third-set was a battle royal as the pair shared five breaks and third-seed Kerber refused to yield until the final phase of the 2hrs, 16mins match.
The German played some great line shots to frustrate the Russian and level at 5-5 before Sharapova held her serve, then used her third and final break to take the match.
"All credit to Angelique, she played a great match," said Sharapova, who claimed the fourth Grand Slam title of her career at Roland Garros last year.
"I won this tournament last year on the way to the French Open so I am really pleased to get back into the final again."