The third round of the 2013 World Rally Championship, which starts from Guanajuato on Thursday evening, will be the first time the official Citroen team has been without its nine-time world champion Loeb since Rally New Zealand 2002.
Of the 55 points Citroen has accumulated so far this year, Loeb has contributed 43, with both Hirvonen and Sordo struggling to find early-season form.
But Matton still has faith in the duo.
"I am still confident that Dani and Mikko can do a very good job in Mexico and for this year," said Matton.
"Sure, Sebastien Ogier, since the start of the year, is putting the level very high, but I am confident with our team.
"Even though Mexico will be the first gravel rally for Dani, it's a rally that will be good for him - it's fast with a lot of grip."
Whatever happens in Mexico this week, Matton says he has no intention of asking Loeb to return to the team for more than the planned outings in Argentina and France.
"This is not the plan," said Matton. "The discussion and negotiation for this year was to ask him to do four rallies this year.
"At the beginning [of those discussions] his choice was to stop at the end of last year. We are happy to have him for the four rallies this year."
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