Miki Koyama ended the first day of W Series running at Misano fastest, having topped the second practice session with a time of 1m34.633s.
Koyama was the first driver to dip below the 1m34s mark, setting her time in the last 13 minutes of the Friday afternoon session and just beating championship leader Jamie Chadwick.
That performance came after Koyama had missed much of the morning session due to an electronics problem.
Chadwick stole the second fastest time of the day from Jessica Hawkins in the closing moments of the afternoon, two tenths slower than Koyama with a time of 1m34.816s.
Hawkins continued an impressive showing so far, coming third in both sessions.
Vicky Piria was fourth in practice for her home race with a time of 1m35.025s as less than a second separated from Piria to Gosia Rdest in 13th.
Zolder winner and Misano practice one pacesetter Beitske Visser - who had initially set the afternoon pace too with a benchmark time of 1m35.057s in the first 15 minutes - was fifth.
After that lap, she was confined to the garage with the engine cover removed from her car for the remainder of the session. Visser reported that her problem was also electronics related.
Fabienne Wohlwend and Alice Powell were sixth and seventh respectively, Powell having set a time fast enough for second in the morning session.
Sarah Moore, Tasmin Pepper and Naomi Schiff completed the top 10.
Marta Garcia, who arrives in Italy fourth in the championship, was fifth in the morning but lost running in the afternoon because gravel had got into her car's engine and damaged the oil pump belt.
The second practice session was delayed by 50 minutes due to the screws in the kerbs at Turns 6 and 16 coming loose, with the kerbs ultimately being removed entirely so that running could resume.
Practice one times
Practice two times