SEPANG, Malaysia - Mercedes worried only about becoming complacent on Sunday (March 30) as it celebrated two wins in two races and its first 1-2 since 1955 in the Malaysian Formula 1 GP.Lewis Hamilton took a pole-to-flag victory and fastest lap ahead of team mate Nico Rosberg, winner of the season-opening 2014 Australian GP in March.Hamilton’s win put Mercedes on top of the Constructors' standings with 68 points, 25 ahead of McLaren which uses the same 'power unit'. Rosberg extended his lead in the Drivers’ championship to 18 points with Hamilton his closest challenger.‘INCREDIBLE DAY’There was no doubt about the car's pace but there were issues about reliability after Hamilton retired after three laps in Melbourne two weeks earlier but both 'power units' stood up to the demands of steamy Sepang where track temperature hit 50 degrees.Rosberg said: "This is an incredible day for the team. For the first time in the modern Silver Arrows era we've achieved a 1-2."Mercedes returned as a works team in 2010 after quitting F1 in 1955. The team's executive director Paddy Lowe said the 1-2 was "particularly pleasing to achieve 1-2 in Malaysia". It's the home of the team's major sponsor."The entire team has spent several years working on this Silver Arrow and today we delivered the final piece of the jigsaw."RIVALS ‘RIGHT BEHIND US’Mercedes was quickest to adapt to the new V6 turbo/hybrid units and the raft of changes brought into the sport for 2014. The win was Hamilton's second for Mercedes since his switch from McLaren and the 23rd of his career.Mercedes F1 executive director Toto Wolf said it was crucial the team pushed forward to help Hamilton and Rosberg's bid for more with reigning champion team Red Bull edging closer.Wolf said: "We cannot become complacent. We still have room for improvement in our package and the race showed once again that the competition is right behind us.”Stay with Wheels24 for the 2014 F1 season – fresh reports every day.