Heidfeld: I was lucky.

Nick Heidfeld has thanked the Williams-BMW team for the decision to bring forward his second scheduled pit-stop in the Monaco Grand Prix, after it allowed to leap-frog team-mate Mark Webber and claim his best finish in Formula One.

The German was bottled up behind Webber and Fernando Alonso in the battle for second in the principality, and the re-scheduled stop allowed him to circulate in clearer air while Webber remained frustrated. The time that Heidfeld was able to make up after his stop then vaulted him past the Australian when he made his second call for fuel - although both remained tied up behind Alonso, who was running a one-stop strategy.

"I think I was just lucky," Formula One's quiet man admitted, "I mean, we decided to bring me in a bit earlier, as we were running into traffic and Alonso had big problems with his tyres. I had the advantage then.

"Alonso was just getting slower and slower - basically, he was slow everywhere. I think he was trying to play the game as in Imola with Michael [Schumacher], going slow at the places where we couldn't overtake to save his tyres. But he just had to start with that so early, because his tyres were in such bad shape, and I just thought I would stay behind for a few laps because his tyres were so bad that they just got worse and worse and, when I got my chance, I would take him.

"I think he did a good job, but his tyres were gone far too early - they just made the wrong tyre choice. As we saw after my stop, it just took a few laps and we were soon behind him again. When he caught a backmarker, I saw that as my chance, and managed to overtake."

Heidfeld used the appearance of Jarno Trulli in Alonso's sight-line to catch the Spaniard napping at the chicane on lap 71, sticking the nose of the Williams alongside the Renault to claim the advantage.

"I think he was distracted a bit," Heidfeld admitted, "The laps before I tried, I wasn't trying too hard. Okay, if he had made a big mistake, I would have tried it, but I saw that his tyres were so bad that I would just wait a few laps because they would get worse and worse. Then, when he was going to lap a Toyota, I think that cost him a bit of speed in the tunnel. I knew I had to get a good exit then."

Second place replaces thirds from Brazil and Malaysia as Heidfeld's best F1 result - and the German was happy that it came at one of the sport's more celebrated venues.

"It feels fantastic," he admitted, "It is the best result I have ever had in Formula One, and it makes it even more special that it is here in Monaco. It is one of my favourite circuits, one of the most difficult circuits in the world, so it is very nice."