Max Verstappen thinks Toro Rosso could have challenged Williams for the occasional podium in 2015 with a better engine.
Verstappen enjoyed a very impressive rookie campaign, finishing fourth in Hungary and the U.S.A, as he became F1's youngest ever driver and points-scorer. However, like parent team Red Bull, Toro Rosso struggled with Renault's uncompetitive and unreliable power unit.
Toro Rosso finished seventh in the constructors' championship, just 11 points behind Mercedes customer Lotus. While the podium places were dominated by Mercedes and Ferrari this year it was another of the world champions' customer teams, Williams, which was best of the rest behind.
Verstappen thinks Toro Rosso's car would have been strong enough to challenge Williams if it had a better power unit inside.
"I think if we had a really good engine we would have been on the podium," Verstappen said. "Not all the time but sometimes when people were retiring, we have to be realistic because Mercedes and Ferrari would have been a bit in front but we could have definitely challenged Williams."
The strength of the team's chassis was clear in Spain when Carlos Sainz and Verstappen locked out the third row of the grid, but only the former finished in the points as Renault's power deficiency was exposed over race distance. Toro Rosso has still not confirmed its engine plans for 2016 but Verstappen is hoping the team can put in a more competitive showing next season.
Asked if he could show even more potential in 2016, he replied: "If we know which engine, yes! I hope we have a bit more horsepower then we can fight with Force India and the Lotus cars because if you see how much they gain on the straight in the races ... In qualifying it is a bit less because you can use DRS and a bit more power there but in the race it's very painful for us.
"Fifty horsepower more makes your life so much easier because you can control the guys behind you -- definitely the Mercedes cars in front can control us and we have to push very hard in the corners to catch up all the time, you can lengthen your stint and everything gets easier."