 Complete the following phrase:  In May 2013, Honda announced their intention to return to the sport in the 2015 season under a works agreement with McLaren to supply power units. The first iterations of the Honda engines proved to be uncompetitive, and Honda spent their first three years under the harsh scrutiny of the public eye as they developed their power unit. McLaren and Honda split after three years, Toro Rosso however, agreed to use Honda engines for the 2018 season as a works outfit. Following a fairly successful season with Toro Rosso, Honda showing fast and potent development with the engines, Red Bull Racing agreed to also take on Honda engines for the 2019 season. Their first victory of the hybrid era was at the 