Spaniard Daniel Moreno (Katusha) produced another strong climb in Sunday's 163.7km ride from Antequera to Valdepenas de Jaen to claim his second stage win and the overall lead in the Tour of Spain.
Moreno edged out compatriots Alejandro Valverde (Movistar) and Joaquim "Purito" Rodriguez (Katusha) by four seconds with overnight leader Nicholas Roche (Saxo) finishing fourth, eight seconds behind.
However, due to the 10 second bonus handed to stage winners, Moreno moved ahead of Roche by one second in the general classification with Giro d'Italia winner Vincenzo Nibali (Astana) moving back up to third, 20 seconds behind Moreno.
It is quite an achievement for the 31-year-old who is not even the leader of his own team and he insisted afterwards that Rodriguez, who currently lies 56 seconds behind Moreno in sixth, remains Katusha's prime candidate to win in Madrid in two weeks time.
"There is always joy when either one of us wins," he told TVE afterwards.
"We spoke and we knew what we were going to do. The intention has always been to slowly but surely make up time on the leaders for Purito.
"The three weeks in the Tour of Spain are very long and I am extremely happy to be the leader today even if it is by just a second."
Roche had only moved into the lead himself when he finished third in Saturday's gruelling 166.6km ride from Jerez de la Frontera to Estepona.
However, the Irishman was still upbeat afterwards and is hopeful of retaking the lead either in Monday's daunting climb to Guejar Sierra or in Wednesday's individual time trial.
"Yesterday was a great day. I said that every day is different and today it has been very different.
"I think I had a good climb, I was fourth and the legs are good. I hope to be strong tomorrow to make up this second or at least not lose more time and I think the time trial will be good for me.
"We still have two weeks to go and anything can still happen. Last year in the Tour of Spain with four days to go everything changed, but I have already had a good performance here in 2010 and with a bit of luck everything will go well."
Nibali finished just a second behind Roche to keep his quest for a second Tour of Spain victory very much alive, whilst another former winner Valverde moved ahead of Chris Horner in the general classification into fourth overall, just 22 seconds back.
The stage itself was relatively well controlled by the peloton as an early five-man breakaway was swallowed up with around 30km to go.
Edvald Boasson Hagen (Sky) then made an attack on the category two climb up the Alto de los Frailes, but the Norwegian never looked like having enough of a lead to get up the steep climb to the finish in the last kilometre.
Moreno then took to the front and comfortably maintained his advantage over Valverde and Rodriguez to claim his second stage victory in six days.