In addition to leading from start to finish and claiming the highest number of stage wins, they put in a faultless run to add panache to their incontestable success, the eleventh of their career together.
Sébastien's exploit sees him join the ranks of those drivers who have forged the legend of the Monte Carlo Rally, including such celebrated names as Sandro Munari and Walter Röhrl (four wins each, including three-in-a-row), Tommi Mäkinen (four consecutive wins), Didier Auriol and Carlos Sainz (three non consecutive wins each).
Ford claimed an early lead in the FIA World Rally Championship after Toni Gardemeister and Jakke Honkanen finished second on their debut for the BP-Ford team.
A career-best result for Gardemeister and eighth place for team-mates Roman Kresta and Jan Tomanek, both behind the wheel of Focus RS World Rally Cars, thrust Ford into a share of top spot after the first of the 16-round series.
The Mitsubishi Lancer WRC05 made a highly-successful debut in the 2005 FIA World Rally Championship and, in the hands of French Tarmac experts Gilles and Hervé Panizzi, claimed third position - the Lancer WRCs best-ever result and the team's first podium placing since the 2001 Safari Rally.
The two Peugeot 307 WRCs of Markko Martin and Marcus Gronholm finished fourth and fifth - but the team was unlucky to miss out on their best result in the Principality after a dramatic end to the event.
Marcus was in a comfortable second place until the first run over the Col de Turini, when he spun and ripped a front wheel off as a result of spectators throwing snow onto the stage.
He had to complete the road section back to service on three wheels, but some swift work from the Peugeot mechanics ensured that he remained in the rally.
1. Loeb Citroën Xsara WRC 2h50m34s8
2. Grönholm Peugeot 307WRC +1m54.7s
3. Gardemeister Ford Focus WRC + 2m08.3s
4. Solberg Subaru Impreza WRC + 2m17.5s
5. Panizzi Mitsubishi Lancer WRC + 2m45.1s
6. Martin Peugeot 307WRC + 3m44.3s
7. Kresta Ford Focus WRC + 4m24.1s
8. Bengue Skoda Fabia WRC + 4m58.1s