Webber, who on Sunday attended his seventh consecutive Red Bull launch, had hit back that it has been clear "for a long time" that he is not part of Marko's "agenda".
Asked about the apparent inequality implied by Marko's comments and Webber's reaction, the 36-year-old driver said on Sunday: "They know I need 100 per cent support.
"You cannot win a world title with only 90, you need 100, and we're going into 2013 with this in place, and I'm comfortable with that," Webber added.
British team principal Horner, who co-owns a GP3 team with Webber, insisted the incident with Marko does not mean Red Bull is not "happy" with its full driver pairing.
"If we weren't happy with Mark then we would never have signed him to be with the team for this year," he said.
Horner added: "As we all know, Helmut can be a little outspoken at times with his comments but he is entitled to his opinion, and sometimes these things can be misinterpreted as well."