Contador's winning margin was just over a minute
Alberto Contador secured overall victory in the Tour of Spain on Sunday to join an elite group of riders.
He is only the fifth rider in history, and the first-ever Spaniard, to win all three of cycling's three-week Tours.
The 2007 Tour de France winner, 25, who rides for the Astana team, also won this year's Giro d'Italia.
French duo Jacques Anquetil and Bernard Hinault, Belgian legend Eddy Merckx and Italy's Felice Gimondi are the other riders to have triumphed in all three.
However Contador's achievement is all the more impressive given he has followed suit in the space of 14 months.
Danish rider Matti Breschel, of the CSC team, took the final stage victory into Madrid.
But it was Contador who attracted all the plaudits after yet another stunning display of three-week stage racing.
"I feel like an enormous weight's been taken off my shoulders," he said afterwards.
"They've been calling me the winner of the race since February and that's a lot of pressure.
"But I'm not going to get a big head now, my family know how to keep my feet on the ground."
Contador claimed his maiden three-week stage race victory when he won the Tour de France in 2007 with the Discovery team.
However later that year he was controversially uninvited to the 2008 race after organisers 'sanctioned' his new team, Astana, despite a management overhaul for a number of doping offences.
Contador turned his attention to the 2008 Giro d'Italia, which he won ahead of Italian Riccardo Ricco, who in July was thrown off the Tour de France for testing positive for banned blood booster EPO.
Contador then went into the Tour of Spain as the overall favourite and put his rivals to the sword in the mountains, while performing strongly in the race's time trials.
American team-mate Levi Leipheimer won the penultimate stage, a 17.1km uphill time trial, on Saturday to close the gap on him to just 46 seconds.
On Sunday, Leipheimer finished second overall, with this year's Tour de France winner, Spaniard Carlos Sastre of CSC, in third.
Stage 21 podium:
1. Matti Breschel (Den) CSC, 2hrs 44mins 39secs
2. Alexandre Usov (Bel) AG2R, same time
3. Davide Vigano (Ita) Quick-Step, same time
Final overall standings
1. Alberto Contador (Spa) Astana, 80hrs 40mins 23secs
2. Levi Leipheimer (US) Astana, +1:01s
3. Carlos Sastre (Spa) CSC +4:31"
4. Ezequiel Mosquera (Spa) Xacobeo, +5:04"
5. Alejandro Valverde (Spa) Caisse d'Epargne, +5:45"