Toto reflects on a rollercoaster 2018 Formula One season
We ended 2018 with victory at the season finale in Abu Dhabi, capping off what has proved to be a remarkable year of racing for Mercedes.
"We have had an exceptional year overall at Mercedes," Toto admitted. "With all the series we have won and that is a highlight for me.
"We have managed to clinch the title with Mick in F3, with George in F2, both Esports titles and the DTM success.
"That is my first highlight. I would say the combination of events after winning DTM on one weekend and then the Drivers' title in F1 and then the Constructors'.
"It feels like a huge weight off our shoulders. The second highlight for me was Lewis' Singapore Qualifying lap as a standout event.
"When he was travelling the world to various fashion shows to launch his collection and many people were saying on Thursday how can you allow him to be in New York and Shanghai? And then he just killed everybody on the track on Saturday."
The team opted for a slightly unusual strategy with Lewis on Sunday, pitting him under the early Virtual Safety Car.
With the SuperSoft tyre proving incredibly durable during the race, it worked well and helped Lewis to an 11th win of the season.
"Lewis had the pace, we could see that," said Toto. "At the end when he saw Vettel coming closer he was able to increase the pace just in the way it was necessary.
"We knew that the SuperSoft could go to the end. It could actually cover a whole race distance.
"So, we wanted to cover against an undercut or VSC or Safety Car in the race later on, where we would have lost a position.
"Knowing that the tyre could go to the end with a little management it was the safer strategy."
Valtteri suffered a difficult evening under the lights at the Yas Marina Circuit, starting off strong and holding onto second position.
However, in the closing stages he started to struggle and eventually dropped to fifth, before pitting for a second set of tyres.
His issues may have been down to a brake problem, but the team needs to properly investigate the situation.
"After the stop we saw some odd braking behaviour, it was on the rear right," Toto explained.
"We couldn't really see what it was, we just saw that the balance wasn't right.
"That's why we made the stop to change the wheel and from then on it was a bit better.
"Before actually making a comment on performance I'd rather see the data."