Sergio Garcia carded a sublime, seven-under-par 64 to move within touching distance of a third Andalucia Valderrama Masters title.
Adverse weather has played havoc with the schedule, preventing Garcia from playing at all on Friday and causing tournament director Jose Maria Zamora to announce the tournament would be shortened to 54 holes before the defending champion began his second round.
Yet there was no lack of rhythm from one of Europe's Ryder Cup heroes as Garcia moved to 10 under for the tournament with a flawless round on Saturday.
Garcia was two under for the day by the turn and made further gains at the 11th and 14th holes before finishing his round with a run of three straight birdies.
That left Garcia four strokes clear of overnight leader Ashley Chesters, who also went bogey-free but made just one birdie during his second 18 holes.
Marc Warren, Alvaro Quiros and Gonzalo Fernandez-Castano are all at four under, six off the pace, while Lee Westwood's three-under 68 left him in a tie for sixth with Shane Lowry after round two.