You don't win by luck by qualifying on pole and dominating the race.
He was brilliant at Interlagos in the rain that year too (remember him overtaking Hamilton and his move was keeping Hamilton away from the championship, before Glock's tyre gave up on the last lap - Hamilton couldn't get near Vettel).
Luck was Hamilton's win at Monaco that year, where he crashed into the wall, got a puncture, and the timing of the forced pit-stop meant he was always on the best tyres (so he got fresh inters which gradually turned to slicks as the track dried - others had to pit for inters (which cooked as they still had the tread blocks)
and dry tyres). Hamilton drove well that day, crash aside, but it wasn't up there with Silverstone or Monza.
OK, one of the best wet weather wins in the last decade then. Though Button, as good as his drive was, did crash into and end the race of two cars (Hamilton and Alonso), which did taint it a little. Still one of, if not the best drive despite that of course.
Also, When vettel was at Toro Rosso. He ran in to the back of RB Webber in the rain. And he cried again
Caused by Hamilton speeding up and slowing down constantly under the safety car, which is why that's banned.