Defending Vuelta a Espana champion Primoz Roglic claimed victory in a tough time-trial on Tuesday to regain the lead in the overall standings with five stages remaining.
With his fourth stage win on this Vuelta so far the Slovenian retook the leader's red jersey from Ineos captain Richard Carapaz with the pair having played cat-and-mouse with the race lead for all of this Tour.
Now 39 seconds adrift, gritty Ecuadorian climb specialist Carapaz has had the overall lead on five stages, while Roglic now goes into his eighth stage in the leader's tunic.
"We will continue fighting," Carapaz promised after the stage where he clung on grimly at times. "The Vuelta is still wide open. We've still got lots of chances, there's some very hard stages still to come, and there are lots of opportunities to make a move."
The tight 2020 title race looks like it will only be decided on the final mountaintop finish on Saturday on a race cut to 18 stages instead of 21 and raced in much colder than usual conditions with the course set largely in the north-west this year.
Britain's Hugh Carthy sits third ahead of the race's climax on Sunday, while Ireland's Dan Martin dropped to 1min 42sec off the pace in fourth.
Few had expected anything other than Roglic winning this long 33.7km individual race against the clock on stage 13 and the Jumbo-Visma rider remains the favourite to defend his title with doubts still lingering however over his metal toughness.
The advantage gained over Carapaz and Carthy was less significant than it might have been, and a surprise champion remains possible, with the chasing pair still within a minute of the lead.
Ireland's Dan Martin, in fourth, might also have saved gas on the time trial for further opportunities up the road.
"Better to be 39 in front than 39 behind," argued Roglic. "We need to keep focus, the guys are really strong and we will fight for it."
Roglic's powerful showing on the ascent of the Mirador de Ezaro's slopes might have surprised those wondering if fatigue might kick in for the 31-year-old this week.
"It's beautiful," added Roglic. "It's been a long time since I won a time-trial. It's a super nice day. I feel strong, surprisingly."
Roglic led the Tour de France this season only to let the lead slip from his grasp on the penultimate day during a long and tricky time-trial as he was overtaken by compatriot Tadej Pogacar.
"We all know it's not really a fun thing to do a time-trial but today I had the legs and I could do a nice time trial," Roglic said.
Wednesday's 204km run from Lugo to Orense in Galicia ends with a short, sharp climb where Caprapaz or Roglic might easily take 20 seconds.
But Saturday's stage is where the Vuelta will be really won or lost as the race finishes with a category 1 climb followed by a beyond category hilltop finish.
Results and standings after the 13th stage of the Vuelta a Espana on Tuesday, a 33.7km time trial between Muros and Mirador de Ezaro:
1. Primoz Roglic (SLO/Jumbo) 46mins 39sec, 2. William Barta (USA/CCC) at 1sec, 3. Nelson Oliveira (POR/MOV) 10, 4. Hugh Carthy (GBR/EF1) 25, 5. Bruno Armirail (FRA/FDJ) 41, 6. Mattia Cattaneo (ITA/DEC) 46, 7. Richard Carapaz (ECU/INE) 49, 8. Remi Cavagna (FRA/DEC) 58, 9. David De la Cruz (ESP/UAE) 59, 10. Jasha Sutterlin (GER/SUN) 1min 07sec.
1. Primoz Roglic (SLO/Jumbo) 49hrs 16min 16sec, 2. Richard Carapaz (ECU/INE) at 39sec, 3. Hugh Carthy (GBR/EF1) 47, 4. Dan Martin (IRL/ICA) 1min 42sec, 5. Enric Mas (ESP/MOV) 3:23, 6. Wout Poels (NED/BAH) 6:15, 7. Felix Grossschartner (AUT/BOR) 7:14, 8. Alejandro Valverde (ESP/MOV) 8:39, 9. Aleksandr Vlasov (RUS/AST) 8:48, 10. David De la Cruz (ESP/UAE) 9:23