Spain's Alejandro Valverde missed out on winning the third-stage time-trial at the Tour of Andalusia to Belgian Victor Campenaerts by just one second, but did take the overall lead of the race on Friday.
Overnight leader Alberto Contador finished third, six seconds back on Campenaerts, to fall one second behind compatriot Valverde in the general classification.
"The two days left are in theory easier than the previous ones. In my head I thought coming out ahead today would mean winning the Tour but Alberto is only a second back," said Valverde.
"One second is nothing. You can't be relaxed and even less so with Alberto behind, who is a great strategist and has shown he is very strong.
"Until I cross the finish line on Sunday, the Tour is not won."
Team LottoNL-Jumbo rider Campenaerts faced a nervous wait after logging a best time of 14mins 55secs for the 11.9km route around Lucena.
Valverde and Contador were two of the last three riders to set off and were both inside Campenaerts' time through the intermediate splits of the stage, but failed to hold onto the finish line.
France's Thibaut Pinot, who beat Contador to Thursday's queen stage, was fourth to drop to third overall, six seconds behind Valverde.
Contador is racing for the first time with new team Trek-Segafredo and believes his lack of rhythm so early in the season may have cost him a first ever overall win in Andalusia.
"The truth is that I just started racing and even though I felt my legs were really good, I also felt I lack still a bit of competition rhythm," said the two-time Tour de France champion.
"It's a pity that there are not two more mountain stages where Alejandro and I could continue the fight between us.
"For me, I think it's complicated to take the overall because the two stages left are more designed for sprinters.
"This year this race is a bit unusual, with the hardest stages at the beginning and that limits the possibilities a lot."
Saturday's penultimate stage takes the riders 179.3km from La Campana to Seville over three category-two climbs before a flat finish.
© 2017 AFP