Max Orrin and Renato Paratore overcame difficult weather to card five-under-par 68 for a share of the Nordea Masters lead on Thursday, while Henrik Stenson could only shoot par.
Englishman Orrin, ranked 469th in the world, turned in a card blighted only by a double-bogey six at the third, while his Italian co-leader battled back after going two over through four holes.
The pair have a one-shot advantage over Welsh duo Jamie Donaldson and Bradley Dredge, while the lowest-scoring home hope Sebastian Soderberg is another two strokes back.
"It was tough out there," said Orrin. "There were a lot of swirling winds and cross winds as well, so it was difficult to judge clubs. But I managed to put a good score together in the end, so I'm very happy with that.
"I've been playing well recently and putting some good numbers on the board. There are some really good signs with my putting. I'm just really enjoying being out there at the moment."
Defending champion Matt Fitzpatrick could only shoot par to sit alongside 2016 Open winner Stenson, while the in-form Alex Noren - fresh from his BMW PGA Championship triumph - carded a 75 on home soil.