With just the 1.9km Karlstad super special still to run, the Subaru Impreza driver, a multiple Norwegian champion, has a relatively comfortable 34.2sec advantage over Yazeed Al Rajhi.
The day didn’t start well for Grondal, who dropped a minute when he left the road on SS2, but a succession of rapid times since, including stage wins on SS4, SS5 and SS7, enabled him to pull clear of his rivals.
“It’s been an incredible day,” said Grondal. “On the first stage my co-driver had to get out and change the air filter after it was clogged with snow but after that it’s been perfect. We’re not taking any big risks so we have a little extra in our pocket if we need it. For now though our rhythm is pretty much perfect.”
Al Rajhi, from Saudi Arabia, was the fastest WRC 2 driver on SS6. Despite having to overcome a broken differential, the Ford Fiesta RRC driver has consistently finished in the top three stage times.
Championship leader Sepp Wiegand is third, 1m07.7s behind Al Rajhi. “I think in the beginning it was not so good because everything was new and I had to find a good rhythm and a better feeling for the snow and the ice,” said the Skoda Fabia S2000 driver.
“On the last stage (SS7) we had a problem with the brakes but basically I’m happy because the afternoon loop was better than the first and so tomorrow, as we learn more and more, we should be faster and faster.”
Ukrainian driver Yuriy Protasov is a distant fourth in his Subaru, 2m 28.1s behind Wiegand, with Mitsubishi driver Nicolas Fuchs rounding off the top five 1m12.3s further back.
One of the pre-event favourites for the class win, Eyvind Brynildsen, retired at the midday service. The Norwegian collected a 1min40sec penalty on Thursday night after his Ford Fiesta RRC refused to start.
The Norwegian mounted an impressive recovery on Friday morning, taking stage wins on SS2 and SS3, but he had to stop after SS4 when team engineers discovered a crack in his car's engine block.