Venezuela's Pastor Maldonado claimed his maiden Formula One win, and handed Williams their first since 2004 with a dramatic victory in the Spanish Grand Prix on Sunday.
Spaniard Fernando Alonso finished second with Finn Kimi Raikkonen in third as Maldonado made the most of inheriting pole position from Lewis Hamilton after the Briton was relegated to the back of the pack on Saturday.
McLaren driver Hamilton finished in eighth place at over a minute behind as Maldonado won a thrilling duel with Ferrari's former two-time world champion Alonso.
Alonso's runner-up place gave him 18 points and the championship lead at the expense of defending world champion Sebastian Vettel, who was sixth in a Red Bull having started from seventh on the grid.
Maldonado's maiden win handed Williams their 114th win overall, but their first in the series since fellow South American Juan Pablo Montoya won the Brazilian Grand Prix in 2004.
The 27-year-old Maldonado had become the first Venezuelan driver to take pole when he was elevated from second place on the grid late Saturday following Hamilton's disqualification for fuel irregularities.
He becomes only the second Venezuelan to score a point, following Johnny Cecotto at the United States (West) race at Long Beach in 1983. Cecotto finished sixth, claiming just one point, for the Theodore team.
In only his 24th Grand Prix, Maldonado drove with great composure in the closing stages to make the most of his team's clever strategy by holding off local hero Alonso as the pair battled over the final laps.
In recognition of his efforts throughout what was an extraordinary race, 2007 champion Raikkonen and Alonso lifted Maldonado on their shoulders on the podium.
Frenchman Romain Grosjean came home fourth in the second Lotus ahead of fifth-placed Japanese Kamui Kobayashi of Sauber and Vettel.
A late charge by Vettel enabled him to push up to sixth by passing fellow-German Nico Rosberg, who was seventh for Mercedes, and Hamilton, who also drove superbly to rise from 24th and last on the grid to finish eighth.
Hamilton's McLaren team-mate and compatriot Jenson Button came home ninth and German Nico Hulkenberg was 10th for Force India on a day when Maldonado became the fifth different winner in five races so far this year.