FIRST ROUND LEADERBOARD:
-5 I Poulter (Eng)-4 Yih-Shin Chan (Tai), E Els (SA) -3 A Hansen (Den), K Ichihara (Jpn), T Levet (Fr) -2 N Fasth (Swe), S Kjeldsen (Den), Chi-bing Lam (Sin), Wen-tang Lin (Tai), P Mickelson (US), J Randhawa (Ind)
Selected others:+2 P McGinley (Ire), +3 MA Jimenez (Sp)
Poulter won the first of his seven European Tour titles in 2000
Ian Poulter carded a five-under-par round of 66 to lead the Singapore Open by one shot after a rain-affected first day at the Sentosa Golf Club.
Returning to action after six weeks, he dropped only one shot to lead from Ernie Els and qualifier Chan Yih-shin.
World number two Phil Mickelson holed his second shot for an eagle en route to a 69 for a share of seventh place.
Padraig Harrington was level par after 10 holes, one of 78 players who must complete round one on Friday morning.
It was a timely return to form for Poulter, currently 29th in the Race to Dubai standings, with next week's new World Golf Championships event in Shanghai and the Hong Kong Open leading up to the season-ending Dubai World Championship at the end of November.
"I am always looking for a win. Whether it's European Tour, Asia or the PGA, I want to win every week," said the world number 21.
"I didn't know what to expect this week. I have practised pretty hard over the last three weeks trying to get ready for seven weeks on the bounce.
"As many balls as you hit on the range, you don't know what it will be like, that is just my fourth round of golf in seven weeks."
The course is in wonderful condition but it is also very difficult with the rough being so thick
Els was pleased with his play from tee to green but expressed frustration with his putting, after squandering a number of chances to shoot a much lower total.
"I left a lot of putts out there and that's the way it has been," the South African said.
"Some of the putts I feel I am really hitting it on the line I see and make good strokes, but they just don't go in. I'm in a bit of a lull with the short stick, maybe I'll change putters."
Mickelson, whose seven-iron shot to eagle the 13th was helped by a fortuitous bounce in a dip around the green, dropped three shots at the Serapong Course.
"The course is in wonderful condition but it is also very difficult with the rough being so thick," the 39-year-old explained.
"The fairways are immaculate and we could lift and clean the ball which helped getting perfect lies.
"I putted well and as the week goes on I think I will get better and better as I get accustomed to the speed of the greens and the grass as well as just getting into the competition aspect of it."
A thunderstorm led to some heavy rain and a delay of almost three hours, meaning half the field will have a very early start on Friday.