Andy Sullivan rediscovered his form in emphatic fashion as he turned in 30 to take the early lead at the Omega European Masters but he had a high-class chasing pack gathered behind him.
The Englishman arrived at Crans-sur-Sierre Golf Club off the back of three missed cuts but had made all 14 this season before that, securing six top tens.
Five birdies on the back nine on Thursday moved him to five under, two shots clear of countryman Chris Wood, Dane Søren Kjeldsen and Belgian Thomas Pieters.
England's Ross Fisher, Swede Robert Karlsson, Finn Mikko Korhonen, South African Charl Schwartzel and Scot Connor Syme were then at two under, with the top nine boasting 41 European Tour titles between them.
Sullivan made four birdies in a row from the 12th and then added another on the 17th as he goes in search of a fourth win.
Wood had played one hole more with birdies on the 13th, 15th and 17th, while Pieters had played eight holes on the back nine, recovering from a bogey on the 11th with birdies on the 14th and 17th and an eagle on the par five 15th.
Kjeldsen made birdies on the second, fifth and seventh in his first seven holes.
Karlsson, Korhonen and Schwartzel all turned in 33 playing the back nine, with Fisher two under through six holes and Syme starting with two birdies.
There were then 16 players at one under including defending champion Matthew Fitzpatrick, last week's winner Matt Wallace and two-time Major winner Martin Kaymer.
