Lionel Messi made the breakthrough from the penalty spot in the 10th minute after he was brought down by Luca Antonini, but Milan midfielder Antonio Nocerino levelled just after the half-hour when he was set up by Zlatan Ibrahimovic.
Messi restored the Catalans’ lead before the interval as Alessandro Nesta was penalised for holding Sergio Busquets, and the Argentine forward’s blocked shot rebounded for Andrés Iniesta to seal the win in the 53rd minute.
“The season is so long, you have different periods,” said Guardiola.
“I don’t think we’re favourites to win the trophy. Bayern are there, Madrid will be there.
“We have won the Champions League twice in the last three years, and have now reached five semi-finals in a row.
“The most difficult thing in the world is to continue because you can win anything once but to do it again is very, very tough. These players are awesome.”
Barcelona have recovered from a difficult spell in La Liga to move within six points of league leaders Madrid, while Guardiola’s side face Athletic Bilbao in the Copa del Rey final on 25 May.
“We are more than satisfied with the season so far and with the effort everyone has put in,” added Guardiola.
“We’ve won three trophies, are into the final of the Copa del Rey, involved in a difficult fight for Liga and have made it through to the Champions League semi-finals.”
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