Fernando Alonso says more work is needed to optimise Honda's more powerful engine after struggling to keep his Aston Martin on track during sprint qualifying at Zandvoort. Alonso and team-mate Lance Stroll received the second specification of Honda's V6 power unit, with the Japanese manufacturer earmarking the Netherlands for its one in-season engine upgrade this year. Shaken down during a filming day after the Hungarian Grand Prix, the new unit produced fresh driveability issues on Friday.

Alonso went off in Turn 1 during SQ1, complaining of heavy vibrations before qualifying 22nd and last, three seconds off the pace. "Free practice was more or less okay but in qualifying we had problems on the engine," he reported. "Driveability was pushing on the braking, so it was difficult to stop the car sometimes because the engine was over-delivering." He added that the SLM mode didn't work, so he could not open the rear wing.

Stroll fared little better, ending 19th: "We were struggling with the driveability, and there were a few other things that weren't quite right."

Honda F1 project leader Shintaro Orihara told Autosport the spec 2 engine changes combustion characteristics, meaning driveability work must largely be re-done: "We need to develop our driveability again."