Lando Norris said Max Verstappen was "not racing very smart" at the Miami Grand Prix and suggested the reigning world champion destroyed his own race.
Verstappen defended superbly for four laps against Norris as the pair battled for second place. They narrowly avoided colliding at one point.
Norris had also run wide at the start while trying to pass Verstappen, a moment which allowed eventual race winner Oscar Piastri through.
Norris later said when racing Verstappen it is either "crash or don't pass."
Speaking after the race, he said the Red Bull driver's aggressive approach to their battle was counterproductive.
"It was fine," he said when asked about it. "He's fighting hard, but it's up to him to do that. He's ruining his own race. He's not racing very smart. We probably could have finished 1-2 today, and he didn't because of that. So yeah, he's fighting, that is always expected, but that's what it is."
Piastri had managed to overtake Verstappen a few laps earlier, although he did not get a move done immediately.
Norris closed the gap on Piastri after getting past Verstappen but never got close enough to challenge for the win.
When asked what was harder, keeping Norris behind or passing Verstappen, Piastri said: "Both very different challenges, I would say. On days like today, our two cars were clearly the best in the field by some margin. I know how strong Lando is as a driver, being his teammate now for a couple of years. It's never easy.
"But also, racing Max is never easy, as we saw. Both very different challenges. In the long term this season, it's clearly going to be a strong fight between Lando and I, but both are challenging."
Red Bull principal Christian Horner said the way Verstappen raced was "brave."
"I was actually surprised that Max was able to hold them back for circa 14 laps or 13. I thought it was a very brave display," he said.
"Arguably, that may be a hurt to our own race because you're fighting hard, your tyres are getting hot, but you're leading the Grand Prix.
"You've got to go for it. I thought he did an outstanding job to keep Oscar behind as long as he did and then Lando."