Sotogrande - Graeme McDowell took full advantage of a collapse by overnight leader Pablo Larrazabal to go top of the leaderboard after two consistent rounds at the Andalucia Masters on Friday
US Open champion McDowell birdied the first and eighth on his outward nine and made up for bogeys at the fifth and ninth holes during an inward nine which included a further four birdies.
McDowell's two-round total of 135 means he leads fellow Northern Irishman Gareth Maybin by two shots, with Sweden's Niclas Fasth making up for a disastrous opening round 73 with a superb 66 to move up to third on 139.
In doing so he boosted his chances of closing his deficit to Kaymer in the Race to Dubai.
McDowell currently lies second, and over 900,000 euros behind the German in the standings, but could close the gap significantly if he wins the 500,000 euro first prize.
Larrazabal had opened his account on Thursday with an impressive 66 but the 27-year-old suffered a spectacular collapse with a double bogey as early as the third hole, picking up five further bogeys on the way to the clubhouse.
The Spaniard, however, is still three shots ahead of Martin Kaymer.
The 25-year-old Kaymer needs to finish in the top two this weekend to end Tiger Woods's 281-week reign as the world's top golfer.
But after carding a one-over-par 72 at Valderrama Golf Club on Thursday Kaymer failed to stop the rot and finished the day hovering precariously above the cut on four-over-par 146.
If he fails to finish in the top two England's Lee Westwood, who is not participating as he is resting a calf injury, will replace Woods at the top of the world ranking.
Spain's Miguel Angel Jimenez is still in contention only five shots adrift of McDowell on 140, along with England's Gary Boyd.
Leaderboard:
135 - Graeme McDowell 68-67
137 - Gareth Maybin 69-68
139 - Niclas Fasth (SWE) 73-66
140 - Miguel Angel Jimenez (ESP) 70-70
141 - Damien McGrane 68-73, Peter Hedblom (SWE) 71-70, Raphael Jacquelin (FRA) 71-70
142 - Gonzalo Fdez-Castano (ESP) 71-71, Darren Clarke 72-70
143 - Sergio Garcia (ESP) 70-73, Richard Green (AUS) 72-71, Pablo Larrazabal (ESP) 66-77
144 - Shane Lowry 73-71, Fabrizio Zanotti (PAR) 74-70, Gregory Havret (FRA) 74-70
145 - Anthony Kang (USA) 73-72, Robert Rock 71-74, David Drysdale 73-72, Jamie Donaldson 72-73
146 - Peter Hanson (SWE) 72-74, Stephen Gallacher 75-71, Martin Kaymer (GER) 72-74
147 - Mikael Lundberg (SWE) 72-75, David Howell 76-71