On 15 September 2017, it was announced that Honda would be the engine supplier to Toro Rosso for the 2018 season. As part of the deal, McLaren switched its engine supply to Renault. Honda stated that the goal was to become a top-three engine manufacturer in partnership with Toro Rosso for 2018. The season started off well for Toro Rosso, with the Honda engine proving to be significantly more reliable compared to previous years. Team principal Franz Tost claimed "The Honda is not as bad as it was made out to be by previous partners, the unit is actually quite a special thing" and was actually surprised by the performance and the ultra compact assembly of the unit. In Bahrain, the team managed to finish in P4, Honda's best result since returning to the sport in 2015. As of 2018, Honda had significantly ramped up its F1 efforts, including greater funding, much improved facilities and a much more effective management structure. During the season, Honda's PU developments were fast and effective with the unit being a much more mature variant of the architecture first used with McLaren in 2017. Toro Rosso were more relaxed on the PU dimension requirements than McLaren, allowing Honda to increase the size of various components, some of which the change alone provided a power and reliability boost and despite the size increase, the Honda power unit was still the most compact on the field. At the Canadian Grand Prix, Honda debuted their Spec 2 unit which provided a notable increase in power while also furthering reliability. Red Bull who were running Renault engines for the season had the benefit of watching how their power unit compared to the Honda in the Toro Rosso. After seeing the performance gain of the new Honda and being impressed with their dedication and facilities, RBR announced the termination of their deal with Renault and the formation of a partnership with Honda for 2019 and 2020.