As zorog said, there was an aggregate system. The first session was held on Saturday where all the cars could one lap and carried minimum fuel. This is the session shown in the video. The second session was held on Sunday morning, again each driver had one lap, however this time they had to do so with the amount of fuel they would start the race with. These two laptimes were added together to determine the starting order. Because Raikkonen was almost half a second faster than Alonso in the first session, he can afford to be just under half a second slower than Alonso in the second session whilst still maintaining pole. Therefore he can afford to carry more fuel in the second qualifying session and hence at the start of the race, which gives a strategic advantage, especially at Monaco.
