VALENCIA, Spain, April 20, 2013 (AFP) - Warren, a two-time winner on the European tour, is followed by compatriot Craig Lee after his two under par round of 70 gave him a one shot advantage over the chasing pack at five under.
Birdies at the third, fifth and seventh got Warren off to the perfect start and despite a dropped shots at the ninth and 14th, further birdies on the back nine at the 10th, 12th and 15th made it a very satisfactory round for the 32-year-old.
The best round of the day, though, was from Englishman David Horsey, whose wonderful 66 put him into contention at five under for the tournament.
Horsey is joined on five-under by fellow Englishman Paul Waring, but it was a disappointing day for overnight leader Peter Uihlein as the American's 74 dropped him back to four under overall alongside Raphael Jacquelin, David Howell and Maximilian Kieffer.
However, there was more promising news for local favourite Sergio Garcia as he shot a two under par 70 to move to one under for the tournament and up to 23rd in the overall standings.
Leading and selected third round scores in the European Tour's Spanish Open on Saturday (GBR/IRL unless stated, par 72):
208 - Marc Warren 70-70-68
210 - Craig Lee 69-71-70
211 - David Horsey 71-74-68, Paul Waring 71-71-69
212 - David Howell 70-71-71, Peter Uihlein (USA) 70-68-74, Maximilian Kieffer (GER) 75-68-69, Raphael Jacquelin (FRA) 73-66-73
213 - Magnus Carlsson (SWE) 70-75-68, David Drysdale 73-72-68, Gregory Bourdy (FRA) 72-73-68, Espen Kofstad (NOR) 71-72-70, Eddie Pepperell 70-70-73, Felipe Aguilar (CHI) 68-71-74
Selected:
214 - Paul Casey 72-70-72
215 - Sergio Garcia (ESP) 72-73-70