The Belgian, making his 185th start to move past Sébastien Loeb on the WRC’s all-time appearance list, posted a benchmark of 4min 33.1sec on his third and final pass of the brand-new 6.31km Nawisa test. Neuville finished 1.8sec clear of championship rival Oliver Solberg, who led the Toyota Gazoo Racing charge in only his fourth start for the team.
Nawisa offered a punishing early taste of Safari conditions, climbing through a rocky quarry before descending onto narrow and heavily rutted tracks. Recent rainfall added further uncertainty, with crews reporting slippery surfaces and rapidly changing grip levels.
"I don't think anyone can predict the final result here this weekend," Neuville admitted after his opening run. "We need to find the fine line between going fast enough and not too fast. The conditions are going to be horrendous at some points."
Toyota’s Sami Pajari and championship leader Elfyn Evans followed in third and fourth respectively, while Sébastien Ogier - the only active driver with multiple Safari Rally Kenya victories - rounded out the top five in front of Esapekka Lappi.
"It's more challenging than ever," Ogier noted. "The rain has been intense, so some sections are going to be very, very challenging. It will be about survival."
There was encouragement for M-Sport Ford as Joshua McErlean placed ahead of Takamoto Katsuta in seventh and Jon Armstrong, making his Rally1 gravel debut, finished ninth. Both Irishmen ended the session within five seconds of Neuville’s benchmark.
Adrien Fourmaux completed the top 10 after setting his quickest run on the opening pass before the increasingly rutted surface made improvements difficult.
Competitive action begins this afternoon with SS1 Camp Moran at 14:30 local time.