Fernando Alonso: "We noticed that there was an issue after P3 but we didn't have time before qualifying to do a proper investigation, so in qualifying we managed to do only about 500 metres before we had to stop the car.
"Now all we can do is to do everything we can to make sure we finish the race without any further issues.
"It's been a difficult weekend so far for me - a little bit unlucky because after all Jenson has the same new-spec PU yet he's had zero problems. But as I say it's just a bit unlucky, that's all.
"With regard to the new-spec PU itself, again, as was the case yesterday, I've had too few laps on it so far this weekend to be able to really compare it with the previous one. We're moving in the right direction though - Jenson's result shows that I think.
"Obviously it's painful when you have reliability problems such as these, but at the end of the day it's part of our learning process. We know what we have to do: we have to understand what's still too fragile in the PU, reinforce those parts, and make sure that next year we have a PU that's powerful and strong enough to be capable of fighting at the front."
Jenson Button: "I'm very happy with ninth place. Spa is a tough circuit for our car so I don't think we expected to get the result we did. You've know when you've done a good job, and I feel I did just that.
"We obviously won't be near the front, but our race pace should be better than our qualifying pace was so we'll certainly be competing with the cars that have qualified around us.
"The team have done a great job this weekend, and Honda have brought us a new power unit, so we're looking at a situation of definite improvement. We didn't expect to be this far up in qualifying here, so hats off to the whole team; it's good progress as I say.
"All in all, I'd say it's the best qualifying of our season so far."
Eric Boullier, Racing director: "Fernando had another very frustrating day, failing to complete even a single lap in this afternoon's qualifying session before his car drew to a halt on his out-lap.
"We don't yet know the exact cause of the problem - that'll require a thorough investigation - but it's possible that he may require yet another PU change for tomorrow's race. If that's how things pan out, he'll incur further penalties, but he was always going to start from the back row of the grid anyway owing to the penalties he'd already incurred.
"On Jenson's side of the garage, things are altogether more cheery. He drove very well this afternoon, moving smoothly from Q1, to Q2, to Q3, and ending up recording a very creditable P9 by the end of the qualifying hour, just 1.370s behind Nico's [Rosberg] pole time.
"Tomorrow, as Fernando has already japed, he'll do his best to hang on to Lewis's [Hamilton] flying Mercedes as Lewis inevitably carves his way through the field from the back row. Watching them race their hearts out doing that should make for great TV.
"As for Jenson, who'll be starting from the fifth row tomorrow, there's every reason to expect him to drive one of his typically gritty yet disciplined races to a points-scoring finish, as indeed he did last time out at Hockenheim."
Yusuke Hasegawa, Honda R&D head of F1 project & executive chief engineer: "It was another bitter-sweet qualifying weekend for us, but, to first focus on the positives, Jenson drove brilliantly in qualifying, finishing P9 despite the power-hungry nature of this track. This confirms that our power unit update has indeed performed as expected, and I'm thankful to everyone in Sakura and Milton Keynes for working on the development and engineering of the power units during the summer months.
"On the other hand, Fernando's side of the garage suffered a difficult day. During the final laps of FP3, his ICE showed an oil pressure drop. We started investigating the issue immediately following the session, and, after data checks, maintenance and understanding the risks, we took a team decision to run the car in qualifying. Unfortunately the oil pressure couldn't be maintained, and it was duly necessary to stop the car at the start of Q1.
"We're still investigating the cause of the problem, and we're sorry for Fernando and his team. They've all worked extremely hard this weekend, and in return they've had little set-up time, on top of the penalties they've incurred.
"No doubt tomorrow's race will be difficult, but as usual we'll come back fighting and do our best."
Check out our Saturday gallery from Spa, here.