Lewis claimed his 78th career pole position - his fifth pole as well as his eighth front row place in Spa-Francorchamps, both of which are new records in Belgium.
Valtteri will start tomorrow's Belgian Grand Prix from the back of the starting grid owing to a grid penalty after an engine change.
Today's result marks the 350th front row place for Mercedes-Benz power in Formula One as well as the 10th front row place for Mercedes in Belgium.
Lewis Hamilton: I really love driving in the wet, but I don't think I can quite put into words just how difficult the conditions were out there today. We were all tip-toeing around and you're just praying you don't lock up. We went straight from slicks onto the Inters in Q3 meaning we only had a handful of laps to try and find the grip, understand which parts of the track were dry, and which parts were wet. I went off at Turn 1, then at Turn 12 on my next lap, so I only had one lap left to get the job done, with the track starting to dry out in those final minutes. I knew I had the pace, I just had to find that right balance and that balance is different in every single corner. I love driving like that. I actually thought we were right in the fight if it had stayed dry. I knew it would be close, but I thought I might just have the edge to get ahead of the Ferraris. They've been favourites for a few races now, but we've managed to come out ahead. Sebastian's long-run pace looked very strong yesterday, so tomorrow could be tough. I don't know if we've quite got the pace to win, but you can bet I'll be giving it everything I've got. It's a long run down to Les Combes on the first lap and we know the Ferraris are incredibly fast on the straights, so we'll have to see how it plays out tomorrow.
Valtteri Bottas: This afternoon felt a little strange - you take a very different approach to qualifying when you know that the result doesn't really matter because you have to start from the grid anyway. Our initial plan was actually to only go out in Q1. We changed the plan shortly before the session, thinking that I could give Lewis a bit of a slip stream, but then it started to rain in Q3 so we abandoned the idea in the end. Thankfully, it didn't do any harm to our original plan as we qualified on the Soft tyre which was the compound we wanted to start the race on anyway. It's pure enjoyment to drive on this track, so I'm really looking forward to tomorrow and I'm confident that there will be possibilities coming up. This track offers the chance to overtake and we do have a very good car around here, so I look forward to the challenge and I'll try to have a little fun as well.
Toto Wolff: That was a great lap from Lewis at the end to claim pole position - once again, he showed that when the pressure is on, there's nobody else you'd want in the car. Until the rain came in Q3, it was a very close fight between Ferrari and ourselves, getting closer as the session went on. Then when the rain came, we decided to fuel for the session and give Lewis the best chance to get pole - and that proved to be the right call. In fact, Lewis was the first car to cross the line, so we were worried that the timing was wrong; but in the end, it didn't matter as he put together three brilliant sectors to take P1 by a healthy margin. As for Valtteri, we abandoned the plan for him to tow Lewis in Q3 when the rain came, as it would have been too risky. But we saw glimpses of his true performance in his short qualifying session today, and I hope he can put that to good use tomorrow from the back of the grid. Well done, too, to the entire team at Force India; after the turbulence of the past weeks, P3 and P4 on the grid is a great boost for them.
James Allison: A brilliantly exciting qualifying session, not just because it finished in wet conditions with all of us watching with our hearts in our mouths as Lewis produced his final lap for pole - but also because in dry conditions it was shaping up to be an extremely close tussle between Ferrari and ourselves, as the engines were turned up progressively through the session. We clearly have two very closely matched packages round this circuit. We are delighted to be on pole today and looking forward to tomorrow's race, when we will have the dual task of converting Lewis and the team's good work and bringing Valtteri through from the back of the field. His pace this weekend merits much more than the last row start to which he has been relegated by our unreliability earlier in the season - and we look forward to watching him deliver that pace in tomorrow's Grand Prix.
Check out our Saturday gallery from Spa, here.