SWITZERLAND, 24 July 2015, (AFP) - The Englishman shot a 62 to add to his opening 65 for a 13-under par total of 127.
South Korean duo Seuk-hyun Baek and 2009 USPGA champion Y.E. Yang were in a tie for second, one shot back, after matching 63s, with Swedish amateur Marcus Kinhult three shots further away.
The 27-year-old Sheffield-born Willett eventually finished sixth at St Andrews, and he is intent on improving on that at Crans-Montana.
"It was very, very good, right from the get-go," said Willett, who carded nine birdies against a single bogey.
"I’m better mentally now than I was. Over these last two weeks especially, I haven’t been getting too far ahead of myself, and every time I’ve got in trouble I’ve just taken my medicine and moved onto the next."
Yang described the conditions as "ideal".
He added: "I managed to judge the ball distance better as the ball flies ten per cent further due to the altitude -- it’s beautiful, with the mountains and scenery."
Overnight leader Gregory Havret failed to produce his opening round fireworks, adding a 69 to his 63 for a share of fifth.
Lightning forced play to be abandoned for the day with 36 players having to return early on Saturday to complete their rounds.
Leading second round scores from the EPGA European Masters on Friday. (GBR & IRL unless stated; par 70):
(Note: Play suspended due to lightning with 36 players having to return on Saturday to complete their rounds):
127 - Danny Willett 65 62
128 - Seuk-hyun Baek (KOR) 65 63, Y.E. Yang (KOR) 65 63
131 - Marcus Kinhult (SWE) 65 66
132 - David Lipsky (USA) 66 66, Richard Green (AUS) 65 67, Rikard Karlberg (SWE) 65 67, Marcus Fraser (AUS) 67 65, Raphael Jacquelin (FRA) 68 64, Gregory Havret (FRA) 63 69
133 - Marco Crespi (ITA) 68 65, Tyrrell Hatton 65 68, Bradley Dredge 66 67
134 - Peter Uihlein (USA) 68 66, Lasse Jensen (DEN) 64 70, Anirban Lahiri (IND) 67 67, Matthew Fitzpatrick 69 65
135 - Matthew Nixon 70 65, Alejandro Canizares (ESP) 67 68, Bernd Wiesberger (AUT) 67 68, Peter Lawrie 67 68
136 - Richie Ramsay 70 66, S.S.P Chawrasia (IND) 70 66, Anders Hansen (DEN) 67 69, Richard McEvoy 70 66, Florian Fritsch (GER) 70 66, David Drysdale 68 68, Alessandro Tadini (ITA) 66 70, Masahiro Kawamura (JPN) 68 68, Patrick Reed (USA) 67 69
137 - John Parry 67 70, Kristoffer Broberg (SWE) 68 69, Pelle Edberg (SWE) 65 72, Matthias Schwab (AUT) 71 66, Jamie Donaldson 67 70, Jerome Lando-Casanova (FRA) 68 69, Adrian Otaegui (ESP) 67 70, Julien Quesne (FRA) 67 70, Chris Doak 71 66, Lee Westwood 68 69