Rome - Finland's Tapio Pulkkanen hit five birdies in his opening nine holes to set a blistering pace and top the leaderboard after the first round of the Italian Open on Thursday.
The 29-year-old hit seven birdies in total for a bogey-free seven-under-par 64 at the $7 million tournament at the Olgiata Golf Club in Rome.
South African-born Rory Sabbatini, now competing for Slovakia, is one shot off the lead, with England's former world No 1 Justin Rose among a group of five two shots behind after a round of 66.
"I feel like my putter was really hot today, I didn't make any bogeys so it was really good. I feel like I can make some birdies this weekend," said Pulkkanen, whose only win was a second-tier Challenger Tour event two years ago.
"My first year was a learning year and second year I feel more comfortable.
"I haven't played that well in the Rolex (Series) tournaments so it's a kind of a new situation as well, there's a long way to go but I feel good about my game."
Home hope Francesco Molinari, bidding for his third Italian Open title, hit a level-par 71, along with England's Paul Casey.
British Open winner Shane Lowry of Ireland slipped to a one-over-par 72.
The tournament is making its return to Rome after a 17-year absence from the Italian capital which will host the 2022 Ryder Cup at the nearby Marco Simone club.
Leading and selected first round scores at the European Tour's Italian Open at the Olgiata Golf Club in Rome on Thursday (GBR/IRL unless stated, par 71):
64 - Tapio Pulkkanen (FIN)
65 - Rory Sabbatini (SVK)
66 - Shubhankar Sharma (IND), Kurt Kitayama (USA), Justin Rose, Joost Luiten (NED), Bernd Wiesberger (AUT)
67 - Joachim B. Hansen (DEN), Andrew Johnston, Matthew Fitzpatrick
68 - Soren Kjeldsen (DEN), Daniel Willett, Ross Fisher, Chris Paisley, Matthias Schwab (AUT), Sam Horsfield, Tyrrell Hatton, Adrian Otaegui (ESP), Erik van Rooyen (RSA)
69 - Matt Wallace, Graeme McDowell, David Horsey, Mikko Korhonen (FIN), Julien Guerrier (FRA), Francesco Laporta (ITA), George Coetzee (RSA), Thongchai Jaidee (THA), Aaron Rai, Kiradech Aphibarnrat (THA), Andrea Pavan (ITA), Robert Macintyre, Jordan Smith, Lee Westwood, Alexander Levy (FRA)
71 - Francesco Molinari (ITA), Paul Casey
72 - Shane Lowry