"It's nice to be in contention and to know this golf course well," he said.
"I've played this course more than most, and I know where to hit it. Hopefully, we can build on that more."
Phachara Khongwatmai of Thailand and Nino Bertasio of Italy shared the lead after matching 65s in the second round.
Phachara made seven birdies, including five straight in a bogey-free round, and Bertasio holed eight birdies to be 11 under overall at the European Tour event.
"It was very easy," Bertasio said.
With Westwood at 10 under were fellow Englishman Chris Paisley (69), Marc Warren of Scotland (66), and Yuta Ikeda of Japan (64).
David Lipsky, the runner-up last year, was among a slew of golfers trailing by two, and Europe's EurAsia Cup-winning captain Thomas Bjorn stayed in contention three strokes adrift.
Defending champion Fabrizio Zanotti was at 7 under, and Henrik Stenson was another two shots behind.
Li Haotong of China, who won in Dubai last weekend, finished the round at 1 over and missed the cut by five shots.
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