Tiger Woods surrendered a four-stroke advantage on Saturday to fall into a tie for the lead with South African Ernie Els heading into final round of the season-opening Mercedes Championship at Kapalua, Hawaii.

When Woods vaulted to a commanding halfway lead, it seemed just a matter of how many shots he would win by. After he birdied the first hole to go five strokes clear, the scenario seemed even more likely.

Instead, a combination of sloppy play by Woods and sharp play by Els saw them locked atop the leaderboard at day's end at the picturesque Kapalua Plantation course on the island of Maui.

Els made four consecutive birdies on the front nine on his way to a six-under 67. Woods needed to eagle the par-five 18th to shoot two-under-par 71 and salvage a share of the lead.

The pair were locked at 11-under 208, four strokes clear of defending champion David Duval with 18 holes to play.

Brent Geiberger, who matched Duval and Els with a 67, was the only other player in the 30-man field within striking distance, five strokes back of the leaders.

Tom Pernice shot the best round of the tournament, but his eight-under 65 still left him eight strokes adrift.

Els, ranked fifth in the world, took advantage of an uneven day by the top-ranked Woods.