Chris Froome assumed overall leadership of the Tour of Oman after finishing second behind Joaquim Rodriguez on day four's mountainous queen stage.
Rodriguez launched a decisive attack with just over 1km of the climb to the summit finish on Green Mountain remaining and crossed the line four seconds ahead of Froome.
With general classification rivals Cadel Evans and Alberto Contador finishing a further 18 and 23 seconds further back, the Briton takes the red jersey from Peter Sagan, who was dropped on the ascent, and now leads Evans by 24 seconds overall.
Just as important as moving to the top of the GC, however, was the way in which he stayed close to Rodriguez's wheel and also left Contador trailing.
The Spanish duo are the most explosive climbers of the current generation and they repeatedly distanced Froome on the summit finishes at last year's Vuelta a Espana. His performance today suggests that gap has been bridged, underlining his credentials as a genuine contender for overall victory at the Tour de France.
Froome said: "There's quite a challenging day ahead of us tomorrow, but we have got a great team and we have really come together as a unit here. With a 24-second lead, it might be hard to hold on, but it is a great position to be in and a good, promising sign for us this early in the year.
"Towards the foot of the climb the guys moved me into position. Brad [Wiggins], Pete [Kennaugh] and [Vasil] Kiryienka all did a fantastic job. When you have guys of that calibre and people like Brad pulling for you then it is hard not to be in a good position. That was really fantastic."
It was also a huge statement of intent from Rodriguez, who has made a dramatic return to form after finishing 26 minutes down on the winner at the Tour de San Luis in Argentina only two-and-a-half weeks ago.
Statement of intent
The win also comes a day before the Court of Arbitration for Sport rules on an appeal from his Russian team, Katusha, against being denied a 2013 WorldTour licence by the International Cycling Union.
If, as is expected, the appeal is thrown out, Rodriguez will need to secure a move to a new, licensed team or face the prospect of missing out on a place at the Tour de France.
He is unlikely to be short of suitors after an emphatic display on the Green Mountain, which is around 10km in length and came at the end of a 152.5km queen stage that started in Al Saltiyah In Samail.
Contador (Saxo-Tinkoff) was the first to show, darting off the front of the bunch after a five-man breakaway group had been caught on the lower slopes.
Italy's Vincenzo Nibali (Astana) quickly followed, while a second chase group containing Froome, Rodriguez, Evans (BMC) and the Italian super-climber Domenico Pozzovivo (Ag2r-La Mondiale) also set off in pursuit.
Pozzovivo couldn't keep up the pace, but the remaining three riders bridged to Contador and Nibali as the race favourites all came back together.
But as he so often did at last year's Vuelta, Rodriguez mounted a fresh attack that proved too much for all but Froome, whose valiant fight to get back on to the Spaniard's wheel was enough to claim vital bonus seconds and hand him the red jersey.
Earlier on the climb, previous wearer Sagan was dropped, bringing to an end the Slovakian's two-day dominance of the race.
Stage four result
1 Joaquim Rodriguez (Spa) Katusha, 4:00.00; 2 Chris Froome (GB) Team Sky, +4secs; 3 Cadel Evans (Aus) BMC, +22; 4 Alberto Contador (Spa) Saxo-Tinkoff, +27; 5 Vincenzo Nibali (Ita) Astana, +35; 6 Kenny Elissonde (Fra) FDJ, +43; 7 Johann Tschopp (Sui) IAM Cycling, +52; 8 Rinaldo Nocentini (Ita) Ag2r-La Mondiale, +57; 9 Arnold Jeannesson (Fra) FDJ, +1.01; 10 Yannick Eijssen (Bel) BMC, +1.09
1 Chris Froome (GB) Team Sky, 16:35.05; 2 Cadel Evans (Aus) BMC, +24; 3 Alberto Contador (Spa) Saxo-Tinkoff, +25; 4 Vincenzo Nibali (Ita) Astana, +34; 5 Joaquim Rodriguez (Spa) Katusha, +45; 6 Kenny Elissonde (Fra) FDJ, +49; 7 Rinaldo Nocentini (Ita) Ag2r-La Mondiale, +58; 8 Johann Tschopp (Sui) IAM Cycling, +58; 9 Maxime Bouet (Fra) Ag2r-La Mondiale, +1.15; 10 Arnold Jeannesson (Fra) FDJ, +1.23