The affable Irishman fired an 8-under-par 64 to grab the first-round lead in the $900,000 Algarve Portuguese Open.
This is Harringtons fourth start this season on the European Tour. In his three prior events, hes earned a pair of runner-up finishes and a tie for fifth.
Thats been Harringtons blessing ' and curse ' over the past three years.
Since 1999, the 29-year-old from Dublin has collected 13 top-3 finishes in Europe; however, only two of those have been wins.
In 99, Harrington recorded five runner-up finishes without a victory; still, he managed to eek into the final qualifying spot on the European Ryder Cup team.
Last year, the results were a bit more balanced ' two wins, two seconds and two thirds.
This year, Harrington finished second in the Malaysian Open, which was won by Vijay Singh. And after opening in 63 the following week, he slipped over the weekend to tie for fifth in the Singapore Masters, also won by Singh.
In his last European start, Harrington carded four sub-70 rounds, yet tied Tiger Woods for second place, two shots behind Dubai Desert Classic winner Thomas Bjorn.
Thursday, Harrington posted one eagle, eight birdies and a pair of bogeys en route to taking a two-shot lead over fellow Irishman David Higgins, Englishmen David Lynn and David Gilford, and Swedens Niclas Fasth.
After making the turn in 5-under-par 31, Harrington bogeyed the par-4 10th, but responded by birdieing the par-3 11th and sinking an 18-foot eagle putt at the par-5 12th.
Following a pair of birdies at the 14th and 17th holes, Harrington concluded his day with a bogey on the par-4 home hole.
'You can't complain,' said Harrington. 'I'm not going to allow that bogey to upset me. Today it was just a joy to be out there.'
Defending champion Gary Orr shot a 2-under-par 70 at Quinta do Lago. Colin Montgomerie wasnt as fortunate in the first round, shooting a 1-over-par 73.
Full-field scores from the Algarve Open de Portugal