Jos Verstappen, the father of F1 world champion Max, has criticised Red Bull's Monaco Grand Prix strategy and said the team should have prioritised his son and not Sergio Perez.
Verstappen finished third in Monaco as Red Bull teammate Perez claimed victory at the Principality.
Perez's win was built on the back of an aggressive tyre strategy which put him in prime position to capitalise on Ferrari's huge tactical blunders.
By contrast Verstappen was off his usual high standards all weekend and only inherited a place on the podium after Ferrari called Charles Leclerc in for a farcical second pit-stop.
Jos, who made 107 F1 race starts between 1994 and 2003, has left no doubt who he blames for his son failing to win the race.
"Red Bull achieved a good result, but at the same time exerted little influence to help Max to the front," Jos wrote in a blog post posted to MaxVerstappen.com.
"That he finished third, he owes to Ferrari's mistake at that second stop of Charles Leclerc. The championship leader, Max, was not helped in that sense by the chosen strategy. It turned completely to Checo's [Perez] favour. That was disappointing to me, and I would have liked it to be different for the championship leader.
He added: "I think ten points from Max have been thrown away here. Especially with the two retirements we've had, we need every points. Don't forget that Ferrari currently has a better car, especially in qualifying."
Although Verstappen is leading Ferrari's Leclerc in the championship by nine points, Jos said Red Bull has still not got its car to a place which suits his son's driving style.
"Max's third place was very disappointing," Jos wrote. "We all saw that it was a difficult weekend for him.
"It starts with the car, which simply doesn't have the characteristics for his driving style yet. Max has far too little grip at the front axle. And especially in Monaco, with all those short corners, you need a car that turns very quickly. That was just hard."