Padraig Harrington, currently ranked eighth in the world, is tied for second place with Maarten Lafeber and Sven Struver. The trio completed 18 holes at 6-under 66 in rainy and windy conditions.
Defending champion Jarmo Sandelin opened his defense with a 5-under-par 67 and shares fifth place with Des Terblanche, Simon Yates, Henrik Nystrom and Andrew Pitts.
This is the first event on the 2003 European Tour schedule and is a joint venture between the European Tour and Asian PGA Tour or Davidoff Tour. Sixty players from each tour compete but it was the 30-year-old Randhawa who separated himself from the pack.
Randhawa chipped in for birdie at the second hole and added another birdie at the par-5 third hole. He dropped his only shot of the round at No. 4 but rebounded with an eagle at the par-5 sixth hole. Randhawa closed his front nine with a birdie at the eighth for a front-nine 32.
Randhawa mixed birdies at the 12th, 14th and 16th holes for his lowest score in a European Tour event and his first lead after 18 holes.
'I made a lot of putts, 12-footers and 15-footers,' said Randhawa, who missed six months this year after he broke his collarbone in a motorcycle accident. 'Putting is the key for my game.'
Harrington, who finished second to Retief Goosen on the European Tour Order of Merit for the second consecutive year, was flawless Thursday with six birdies against no bogeys.
'It wasn't quite effortless, but it was comfortable,' he said.
Struver was also bogey-free on Thursday while Lafeber carded one bogey to go along with his seven birdies.
John Daly, the 1995 British Open champion, shot an opening-round 70 to headline a group tied for 22nd that included European Ryder Cup hero Paul McGinley of Ireland. Daly posted a fine first-round score but seemed more impressed with Randhawa's number in the cold, soggy conditions.
'I thought anything under par today would be totally awesome,' Daly said.
Fran Quinn, James Kingston, Adrian Percey, Julien Van Hauwe and Arjun Singh share 10th at minus-4.
Ian Woosnam posted a 1-under 71 Thursday while Jose Maria Olazabal and 2002 European Ryder Cup captain Sam Torrance were eight shots out of first with opening-round 73s.
Full-field scores from the BMW Open