Carlos Sainz Jr. and Stoffel Vandoorne will start the Belgian Grand Prix from the final row of the grid after both drivers took a fresh Formula 1 power unit ahead of Sunday's race.

Sainz qualified 16th for Renault, four places ahead of Vandoorne in P20, but both drivers were due to rise two places on the grid as a result of demotions for Valtteri Bottas and Nico Hulkenberg, both of whom also took new power units earlier in the weekend.

In the latest FIA technical bulletin issued ahead of the race on Sunday, it was confirmed that Sainz and Vandoorne's cars had both been fitted with a fresh set of all six power unit components, resulting in them dropping to the back row of the grid.

Sainz will start 19th ahead of Vandoorne by virtue of qualifying ahead, with Bottas now lining up P17 ahead of Hulkenberg in P18.