According to Christian Horner, Lewis Hamilton was to blame for making his title battle with Max Verstappen more heated.
The Red Bull boss said Hamilton "never knew" Verstappen's ability, adding "another needle" to the battle.
Horner admitted there was a "different respect" between Verstappen and Charles Leclerc this season than last year against Hamilton.
He spoke to F1's Beyond the Grid podcast when asked why Verstappen seemed to give Leclerc more space than Hamilton last year.
Horner replied: "There's a difference. There's maybe different respect with Charles. They raced together as kids and there's mutual respect.
I've never heard Lewis acknowledge Max's ability, so of course, a bit more needle was needed." it.
“You could feel it and you could feel it between the two drivers. Pundits such as Martin Brundle and Karun Chandhok also noted Verstappen's calmer
approach to racing Leclerc than Hamilton.
The reigning champions were embroiled in a battle with Monaco in the opening races of the season