Ronaldo was shown a straight red during Sunday's 2-0 win over Malaga after catching defender Patrick Mtiliga with a flailing arm and breaking his nose.
As part of their appeal against the card, Real presented evidence to the Spanish soccer federation (RFEF) which included video of an incident when Messi used his arms to shake off a Sevilla opponent who was holding him back.
Messi was awarded a free kick and the RFEF ruled that as the referee had not mentioned the incident in his match report it was not relevant and, in any case, no injury had been caused.
"You have to assess the intention of each player," Xavi told reporters on Wednesday.
"Leo wants to carry on playing and Cristiano wants to break free of the defender with a swipe of his arm," added the Spain international, who is one of Barca's club captains.
"Leo is the number one and you can't damage his image in any way. He's humble, hard-working and always thinks about the group. Not like other footballers."
The RFEF's disciplinary committee decided Ronaldo's actions were not wilful or reckless, which would have meant a longer suspension, but that he had been guilty of dangerous play.
Real have said that if their appeal was unsuccessful they would take the case to Spain's Sporting Disciplinary Committee (CEDD), a body overseen by the government sports council (CSD).
"For me, the (Ronaldo) incident is very clear," Xavi said. "It's a red and the two-match ban is extremely fair."
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