The Swede picked up two more birdies on his return to the course following the previous afternoon's abandonment to take him a shot clear of South African Andrew McLardy and Irishman Gary Murphy, who finished their rounds yesterday.
Irishman Peter Lawrie, Dutchman Robert-Jan Derksen, Jean-Francois Lucquin of France and Briton Sam Little also share second place after completing rounds of 66 on Friday morning.
Fasth is still just in running to win Europe's order of merit but conceded it was now a long-shot.
''Three weeks ago I had hopes,'' money-list fifth-placed Fasth told reporters. ''But I have failed to win a second tournament and I have a lot of catching up to do.'' Victory this week and second place in next week's season-ending Volvo Masters would give Fasth a chance to be European number one.
Last year he finished fifth at the Valderrama finale.
After a 45 minute break, Fasth began his second round.
REUTERS BJR KP1724