Maria Sharapova says she has benefited from coach Thomas Hogstedt's work with her since the pair reunited a few weeks ago.
Though Sharapova fell to Caroline Garcia in the first round of Stuttgart this week, the two players had a high-quality encounter that went more than two and a half hours.
Sharapova was playing her first tournament since withdrawing from Miami with an ongoing arm injury, and her first event with Hogstedt since they split in 2013. She said they are still on a trial basis.
"We haven't really made a formal agreement," she told press at Stuttgart. "We're taking it one week at a time. But I'm loving the work I'm putting in and as far as I'm concerned, that's always the important step in the process."
Sharapova split with her previous coach Sven Groeneveld following a first-round defeat at Indian Wells, where she has said her participation had been affected by arm problems.
TC Live discusses Maria Sharapova: