The final 30-minute session ended prematurely following a crash for Ma Qinghua, which left Rowland at the top of the times with a 1m04.799s effort.
Reigning Formula 2 champion Nyck de Vries posted the early benchmark with a 1m05.586s ahead of his Mercedes teammate Stoffel Vandoorne and points leader Alexander Sims.
After five minutes, Porsche’s Andre Lotterer found a 0.3s advantage to move clear as his teammate Neel Jani was lucky to escape without damage after clattering the tyre wall on the exit of Turn 9.
Mitch Evans posted a then-session best of 1m05.046s, but was lucky to do so as the first of two red flags was waved just after he crossed the timing line.
With 16 minutes of the session to go, ex-Toro Rosso Formula 1 driver Brendon Hartley paused the session when a cooling fan had been left on his Dragon Racing car.
The assembly dropped off the car as he rounded Turn 1, causing the stoppage while it was retrieved, and for which he is under investigation for an unsafe release.
Contact between Antonio Felix da Costa and Rowland at Turn 1 will also be assessed, after the DS Techeetah driver appeared to turn in on the Nissan.
But Rowland responded by posting his 1m04.799s run with the maximum 250kW of power to head the session ahead of Felipe Massa by 0.131s.
Ma Qing Hua, NIO 333, NIO FE-005, hits the wall
Andrew Ferraro / Motorsport Images
Before anyone could retaliate, NIO 333 driver Ma shunted heavily at Turn 5 to cause a second stoppage from which practice two would not resume.
He lost the rear of the car under braking and as he tried to recover ran wide and ploughed into the wall.
That meant Evans’ 235kW lap was still suffice for third ahead of BMW Andretti driver Max Gunther and Lotterer, with da Costa in sixth.
Hartley’s difficult run continued as he was then flagged to the stewards for undertaking under the second red flag, having ran 10th quickest.
De Vries slipped to 11th ahead of Pascal Wehrlein and new Jaguar recruit James Calado, as the top 13 all lapped within a second.
Reigning champion Jean-Eric Vergne was just 15th, with Lucas di Grassi beating Sims to 17th.
Sam Bird could only manage 22nd ahead of Jani and Ma, despite the Envision Virgin Racing driver having topped the cooler first practice session courtesy of a 1m04.914 ahead of da Costa and Edoardo Mortara.