Fernando Alonso said his charge from the pit lane to eighth place in Sunday's Austrian Grand Prix was "unexpected" as McLaren benefitted from tyre struggles for cars further up the order to rise into the points.

After qualifying 13th on Saturday, Alonso was forced to start the race from the pit lane after McLaren changed the specification on his front wing and took a new MGU-K on his Renault power unit on Sunday morning.

Alonso vented his frustration over the radio while running P19 early on, only running ahead of teammate Stoffel Vandoorne, but managed to rise through the order during the race to sit on the fringes of the points entering the closing stages.

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Tyre blistering for the likes of Pierre Gasly and Charles Leclerc allowed Alonso to pass for position, which combined with retirements for front-runners Lewis Hamilton and Daniel Ricciardo left the Spaniard eighth at the chequered flag.

"It's completely unexpected, to go from the pit lane to P8 is definitely great," Alonso said.

"In the beginning of the race we were behind a group of cars and we were not able to show our pace. In the second part, a lot of people suffered blisters on their rear tyres, and we didn’t, so we had a pace advantage and we maximised that potential. So I’m happy with P8.

"It was a surprise today with the hotter track temperature, so the blisters became a problem. We suffered them in the first part with the red tyres, so on the yellow tyres we tried to take care as much as we could in the beginning of the stint. Even with that, it was difficult to manage and finish the race."

Alonso was McLaren's sole points-scorer as teammate Stoffel Vandoorne retired in the closing stages while running two laps down, having damaged his car after contact with Gasly at Turn 3 on the opening lap of the race.