Bro, Sweden - Lee Westwood shot an 8-under 64 to lead by three strokes after the second round day at the Nordea Masters on Thursday.
The third-ranked Englishman is at 12 under after playing with a new set of irons ahead of the US Open at the Olympic Club in San Francisco next week.
"The conditions were perfect for low scoring, here was little wind and the greens were pretty pure," Westwood said. "I putted nicely and that has given me a lot of confidence.
"I could have been even lower but I left the ball on the edge of the hole a couple of times."
Although ninth in Europe's 2012 Race to Dubai, Westwood is currently 57th in the European Tour's average putts per round.
"I am here building up all of my confidence," he said. "And the Olympic Club won't be any longer than this course, nor will the rough be any thicker. Maybe here only the fairways are a bit wider."
Peter Hanson of Sweden (68), Scotland's Lloyd Saltman (64) and Carlos del Moral of Spain (67) are just behind Westwood.
Saltman's round is his lowest on the European Tour and included an albatross at the par-five 12th.
"I heard a little clap and then there was a big roar as I started walking, so I knew it must have gone in," Saltman said.
First-round leader Magnus A Carlsson of Sweden followed up his 65 with a 72. Defending champion and countryman Alex Noren had been in danger of missing the cut following a 74 on Wednesday, but a 66 will ensure he plays the last two rounds.
Collated second round scores in the European Tour Nordea Masters at Bro Hoff Slott GC on Thursday (Par 72):
132 - Lee Westwood (ENG) 68-64
135 - Carlos Del Moral (ESP) 68-67, Peter Hanson (SWE) 67-68, Lloyd Saltman (SCO) 71-64
136 - Emiliano Grillo (ARG) 68-68, Michael Jonzon (SWE) 68-68, Ignacio Garrido (ESP) 67-69, Maarten Lafeber (NED) 71-65, Richard Sterne (RSA) 69-67
137 - Richard Bland (ENG) 67-70, Chris Wood (ENG) 71-66, Magnus A Carlsson (SWE) 65-72
138 - Daniel Denison (ENG) 68-70, Roope Kakko (FIN) 70-68, Ross Fisher (ENG) 70-68, Sergio Garcia (ESP) 69-69, Estanislao Goya (ARG) 70-68, Joakim Lagergren (SWE) 70-68, Pelle Edberg (SWE) 69-69, Michael Hoey (NIR) 70-68
139 - Jeev Milkha Singh (IND) 73-66, Mikko Ilonen (FIN) 70-69, Kristoffer Broberg (SWE) 71-68, Felipe Aguilar (CHI) 69-70, Anthony Wall (ENG) 69-70, Andy Sullivan (ENG) 68-71, Thorbjorn Olesen (DEN) 71-68, Alejandro Canizares (ESP) 68-71, Gregory Havret (FRA) 70-69
140 - Scott Strange (AUS) 71-69, Andrew Dodt (AUS) 71-69, Darren Fichardt (RSA) 70-70, Brett Rumford (AUS) 69-71, Tjaart Van Der Walt (RSA) 72-68
141 - Richard Green (AUS) 72-69, Edoardo Molinari (ITA) 72-69
142 - Marcus Fraser (AUS) 72-70
143 - Jaco Van Zyl (RSA) 69-74, Thongchai Jaidee (THA) 73-70, Graeme Storm (ENG) 73-70, Niclas Fasth (SWE) 69-74, Daniel Gaunt (AUS) 71-72
Failed to make the cut:
144 - Hennie Otto (RSA) 74-70, Raphael Jacquelin (FRA) 72-72, David McKenzie (AUS) 72-72
145 - Jose Manuel Lara (ESP) 74-71, Scott Hend (AUS) 73-72
146 - Miles Tunnicliff (ENG) 74-72, Bradley Dredge (WAL) 76-70
147 - Alastair Forsyth (SCO) 74-73, Benjamin Hebert (FRA) 73-74