Katsuta stopped the clocks at 4min 16.2sec on his second pass through the test, ending the session 2.4sec clear of Hyundai driver Fourmaux.
It was an encouraging start to a weekend which brings a significant change inside Katsuta’s Toyota GR Yaris Rally1. Fulton has stepped in to replace Aaron Johnston, who requires additional time to recover following the pair’s high-speed accident at ueno Rally del Paraguay.
Despite having only limited preparation time together, Katsuta said the new partnership had quickly begun to settle.
“James is doing a very good job,” he explained. “We did a couple of days of practice together and, of course, we all know that James is a very good co-driver.
“We haven’t had much time together, so we just need to get the feeling between us, find the same rhythm and have the same focus.
“But it seems like it is going very, very well. Aaron is also trying to help us remotely, so everything should be OK.”
Fulton was equally pleased simply to be underway, saying: “I’m glad to be in the car and I hope we can have a good weekend.”
Fourmaux provided Katsuta’s closest opposition with a best effort of 4min 18.6sec as the Frenchman looks to convert another display of front-running pace into an elusive maiden WRC victory.
“We’re going to have to be good on all the days,” Fourmaux said. “It’s going to be a challenge, and it will be pure performance on Friday. We’ll see what we can do, but we are here to get the best.”
Championship challenger Sami Pajari and Esapekka Lappi shared third place, both 2.5sec from Katsuta’s benchmark.
Lappi’s result represented a strong recovery from an eventful opening pass, when the rear of his Hyundai stepped out and sent him into a half-spin. A brush with a tree prevented the car from falling further off the road, although the incident cost more than 30sec.
“The rear just stepped out and I couldn’t catch it,” he admitted. “It was quite surprising.
“Tomorrow could be damp in the morning and I don’t know how it will affect the road. It will come down to the tyres and tyre management, but first we need to stay in the middle of the road.”
Thierry Neuville completed a tightly-packed Hyundai trio in fifth, 2.8sec off the pace, with defending Chile winner Sébastien Ogier just one tenth further back in sixth.
Ogier, who will equal Jari-Matti Latvala’s all-time record of 213 WRC starts when the rally begins on Friday, was conscious that Thursday’s dry conditions may bear little resemblance to what crews face on the opening leg.
“At the moment it’s dry, but the rain is coming tonight, so not really the best preparation to get into the rhythm,” he said.
“Tomorrow is a difficult stage to start the weekend. It will be important to drive clean and hopefully we can have a smooth weekend.”
M-Sport Ford pair Jon Armstrong and Josh McErlean were seventh and eighth respectively, Armstrong just 0.1sec quicker than his team-mate, while Oliver Solberg took ninth.
Championship leader Elfyn Evans ended shakedown 10th, 10.2sec behind Katsuta, but his attention was focused firmly on what lies ahead.
As championship leader, Evans will open the road on Friday and found considerable loose gravel on his first pass – leaving him hoping forecast overnight rain arrives to reduce the cleaning effect.
“It’s horrendous in there,” he said. “If it stays dry, then it’s going to be very difficult, but we’re hopeful for some rain tonight, which will help.”
Pajari, who trails Evans by 20 points after winning the previous three rallies, starts immediately behind his Toyota team-mate. Solberg follows third on the road, with all three highlighting loose gravel as a potential factor during Thursday’s first taste of the conditions.
The rally begins on Friday morning with the 22.94km Turquía stage, the first of six tests forming an extensively revised opening leg.