An explosive finish on Old Willunga Hill gave Movistar's Alejandro Valverde the win at the end of the fifth stage of the Santos Tour Down Under.
The team did a phenomenal job for me today, and I also want to thank everyone that's supported me over the past 18 months. It's been quite emotional for me.
Valverde rode side-by-side to the finish with Simon Gerrans (GreenEDGE) and only just pipped the Australian road champion at the line.
The performance of the Spaniard completes a successful comeback to the sport after a suspension for involvement in the Operation Puerto doping case.
Portugese rider Tiago Machado (RadioShack-Nissan) was the third rider to finish the 151.5km stage from McLaren Vale to Old Willunga Hill.
"I'm happy, I've had a two-year paid training camp, chasing summer, so it's nice to be actually racing," Valverde said at the finish.
"The team did a phenomenal job for me today, and I also want to thank everyone that's supported me over the past 18 months. It's been quite emotional for me."
Gerrans now leads the overall classification, but he and Valverde are effectively tied in time which means the race is set for an exciting finale in Adelaide.
"It's fantastic, it's a pretty special moment for GreenEdge," said Gerrans. "In our first WorldTour outing, to have the lead going into the last stage is pretty good.
"I gave it everything I had but unfortunately I might have hit out a little bit early with Valverde but I wanted to get the inside line on that corner, [but] it was a drag race to the line and he got me by half a wheel."
Rather than Valverde's stage win breaking the tie, under race rules it is the riders' aggregate stage placings that decide who leads.
Here Gerrans holds a massive lead, having finished 35th, third, 20th, 17th and second.
Until Saturday's win, Valverde (Movistar) had finished behind him each day - 58th, fourth, 54th and 33rd.
This means Valverde must gain time on Gerrans during Sunday's stage, which will be highly unlikely.
Sprinters dominate the flat stage and Valverde is much more a climber than a fast man.
The day started with an early break led by Australians Stuart O'Grady (GreenEDGE) and Nathan Haas (Garmin Barracuda).
They were joined by Thomas DeGendt (Vacansoleil), Miyazawa (Saxo Bank), Kristof Goddaert (AG2R) and Andrew Fenn of Omega Pharma Quickstep.
The early selection rode out to a lead of 8min 30sec but the gap was destined to fall as the climbers waited for their chance on Willunga.
Along the way the six breakaway riders swept up all the honours on offer in the two intermediate sprints and the first king of the mountain (KOM).
The peloton started to pull things back at the 80km mark and the time gap began to fall steadily with Sky, BMC, Movistar and Rabobank regularly contributing to the chase.
The majority of the break was eventually pulled back on the first climb up Old Willunga Hill, with Haas the only rider to resist.
Haas was the first over the first climb but a powerful selection of 20 riders, which included Gerrans and Valverde, made the chase and caught Haas before the second ascent.
That group eventually splintered on the final climb up Willunga and a smaller group was left to fight for the win.
It is the second time in the Tour's 14-year history that there has been a tie going into the last stage. Spaniard Mikel Astarloza won the 2003 Tour on a countback from Dane Lennie Lange Kristensen.
Stage 5: McLaren Vale - Old Willunga Hill 151.5km
1 Alejandro Valverde (Spa) Movistar 3:45:48
2 Simon Gerrans (Aus) GreenEDGE
3 Tiago Machado (Por) RadioShack-Nissan 0:00:02
4 Michael Rogers (Aus) Sky Procycling 0:00:04
5 Rohan Dennis (Aus) UNI SA - Australia 0:00:07
6 Edvald Boasson Hagen (Nor) Sky Procycling 0:00:12
7 Javier Moreno (Spa) Movistar 0:00:13
8 Jan Bakelants (Bel) RadioShack-Nissan
9 Jack Bauer (NZl) Garmin-Barracuda 0:00:26
10 Eduard Vorganov (Rus) Katusha
1 Simon Gerrans (Aus) GreenEDGE 18:49:24
2 Alejandro Valverde (Spa) Movistar
3 Tiago Machado (Por) RadioShack-Nissan 0:00:08
4 Michael Rogers (Aus) Sky Procycling 0:00:14
5 Rohan Dennis (Aus) UNI SA - Australia
6 Edvald Boasson Hagen (Nor) Sky Procycling 0:00:18
7 Jan Bakelants (Bel) RadioShack-Nissan 0:00:19
8 Javier Moreno (Spa) Movistar 0:00:23
9 Michael Matthews (Aus) Rabobank 0:00:29
10 Eduard Vorganov (Rus) Katusha 0:00:32.