Honda has only just reached the level of engine performance it was hoping to see from the start of 2017 pre-season testing, according to F1 boss Yusuke Hasegawa.
McLaren and Honda's relationship has come under serious strain this year after the Japanese manufacturer delivered a third successive uncompetitive and unreliable power unit. The team currently lies ninth in the constructors' championship, narrowly above a Sauber outfit running a year-old Ferrari engine.
Recent Honda upgrades have shown signs of progress and Fernando Alonso was able to claim fastest lap on route to finishing sixth in Hungary, while also performing well at the more power-sensitive Silverstone circuit for the British Grand Prix.