Vilamoura - Belgium's Nicolas Colsaerts and Andy Sullivan of England shared the first round lead at the Portugal Masters on Thursday after early fog held up play at the par-71 Oceanico Victoria Golf Club on the Algarve coast.
Colsaerts, 32, was one of the early starters after a 55-minute delay and took advantage of a pair of eagles in a sparkling seven-under round of 64 to put the 2012 Ryder Cup winner firmly in contention.
Colsaerts, chasing a 10th professional victory but only his third on the European circuit had a putt for 59 in last year's opening round before falling off the pace.
His last victory on the EPGA Tour was in 2012 when he defeated Northern Ireland's 2010 US Open champion Graeme McDowell to lift the World Match Play Championship.
Sullivan, 29, drained eight birdies and would have held the outright lead had he not two-putted from close range for bogey at 16 for the only blemish on an equally impressive scorecard.
"I had a bit of a scrappy start but I grew in confidence as the day went on and played well down the stretch," said Sullivan, who won the South African Open in January and the Johannesburg Open two months later.
Four players are locked on 65, and one shot back, including Belgian Thomas Pieters, who caused a sensation earlier this season by winning his first two tournaments, in three weeks, at the Czech Masters and Dutch Open.
Also one shot back are Scotland's 40-year-old David Drysdale, who has never won a European title, and who had to make a 30ft putt on the 18th green in Perth last October to maintain his 2015 playing card.
Spaniard Eduardo De La Riva and South African Thomas Aiken also both fired rounds of six under.
Germany's former US Open and PGA champion Martin Kaymer settled for a one-under 70 as did Irish two-time British Open winner Padraig Harrington who had an eagle at the par-5, 17th in an erratic round that also included a triple bogey seven at the par-4 seventh hole.
Defending champion Alexander Levy has work to do if he is to retain the title he won last year after a one-over 73 that left him eight shots back.