Francesco Laporta made five birdies in his final five holes to leapfrog England's Matthew Fitzpatrick and take a one-shot lead into the weekend at the Abu Dhabi HSBC Championship.
Fitzpatrick stayed bogey-free through 36 holes as he fired a 67 to get to nine under but Italian Laporta came home in 30 in a round of 63 to edge ahead of the Yorkshireman.
Spain's Rafa Cabrera Bello was alongside 2016 Ryder Cup team-mate Fitzpatrick, with 2017 Masters champion Sergio Garcia, China's Li Haotong and Italian Renato Paratore at eight under.
World number one Brooks Koepka had opened with a 66 in his first competitive round after three months out with a knee injury but he had a day to forget in round two.
The American made two double-bogeys in a 75 that saw him slip seven shots off the lead and just two inside the cut mark.
Fitzpatrick experienced the first winless full season of his professional career in 2019 as he finished second five times worldwide but birdies on the 13th, 15th, 17th, 18th and eighth in Abu Dhabi put him in contention for an early victory in 2020.
"For me every event is the same, you're here to win," he said.
"For the first week of the year, to have no bogeys, couldn't ask for a better start, really. I just played really disciplined golf and it's worked out well so far."
Laporta's five closing gains added to birdies on the second, third, ninth and 11th as he carded the lowest round of the week so far.
"I gave myself a lot of opportunities for birdies and so when I had the opportunities, I took them," he said. "Every time I was putting for birdie, I made it. It was a great day."
Cabrera Bello carded a 68, one shot better than countryman Garcia and Li, while overnight leader Paratore had to settle for a level-par 72.
England's Lee Westwood was in the group at seven under, one clear of Scotsman David Law.