The new 206WRC has now led both events it has entered this year. However, the result was achieved on a 2.40km super-special, the only stage yesterday, and with far more competitive stages to come, is unlikely to have much bearing on the overall result.
In his first drive in a Peugeot 206 in a round of the world championship Gronholm finished 0.1sec ahead of the Mitsubishi of Belgium's Freddy Loix and 0.4sec in front of Spain's Carlos Sainz, driving a Toyota Corolla. Loix upstaged his team-mate and the reigning world champion, Tommi Makinen, who tied for 12th fastest time with the winner of the last round, the Rally of Argentina, Juha Kankkunen.
The Scot Colin McRae was equal fourth fastest in a Ford Focus with the Toyota driver Didier Auriol, who leading the championship with Makinen. The Briton Richard Burns was just over a second off the pace in seventh place.
"The stage was fairly average," McRae said. "It's very hot and very dusty. We're looking to tomorrow."
McRae's younger brother, Alister, topped the Formula Two category by over two seconds in his Hyundai Coupe, more than two seconds clear of his more experienced Swedish team-mate, Kenneth Eriksson.
Earlier, race officials had shortened the course's length after drivers' concerns over the quality of the roads that could turn the event into a lottery.