Fernando Alonso was said he felt "good potential" in Renault's Formula One car during his test at Barcelona's Circuit de Catalunya on Tuesday.
The 100km test is part of Alonso's preparation for his return next year, when he will take the place of Daniel Ricciardo. The two-time world champion left F1 at the end of 2018 after four disappointing seasons with McLaren.
"I think the car was a nice surprise," Alonso said on Tuesday. "We know the car is performing well at the last couple of races and I felt the grip and certainly good potential in it.