(CNN) -- New world number one Lee Westwood is one shot behind leader Francesco Molinari after the first day of the HSBC Champions Challenge in Shanghai, China.
Italian Molinari carded an opening round seven-under-par to lead the field, with Westwood one shot back and Tiger Woods, who saw his 281-week run at the top of the rankings ended by the Briton, still in the hunt on four-under-par.
Japan's Yuta Ikeda, Henrik Stenson of Sweden and South Korean Seung-yul Noh are all tied for third position, two shots behind Molinari.
It was a strong showing from 37-year-old Westwood -- playing only his second stroke-play tournament in the last three months after being troubled by a calf injury -- as he dropped only one shot on his way to a 66.
Westwood said he does not need to prove he is worthy of his new-found status, but admitted it was good to show everyone what he is capable of.
"I don't think I need to reinforce why I'm No. 1 in the world," he told the PGA Tour's official website.
"I think you get there as a result of having good performances. But it's nice to go out there and show everybody that there is a particular reason why I got to that stage."
"I was a little rusty in places with my scoring, but I putted nicely. All in all, I think I probably deserved about a 66."
His Ryder Cup teammate Molinari was in sparkling form, hitting an impressive seven birdies in a bogey-free round of 65.
Currently sitting in a three-way tie for sixth place, Woods knows he can regain his spot at the top of the world rankings, which he occupied for over five years, with victory in Shanghai.
Woods, a winner of 14 major championships, was happy with his form at the Sheshan International Golf Club.
"I hit a lot of good golf shots," said Woods. "I felt like I was able to control my distance well coming into the greens, and also putted really well today."
The American is tied with Spain's Pablo Martin and Luke Donald, with British Open winner Louis Oosthuizen and Phil Mickelson also part of a large group on three-under-par.