Last year's beaten finalists were out of sorts for large parts of the game at Ewood Park, but led at the break thanks to Alvaro Negredo's goal on the stroke of half-time.
However, captain Scott Dann grabbed a deserved equaliser for the hosts 10 minutes into the second period.
Despite being held by the Championship side, Pellegrini was relaxed after the game, stating that Gary Bowyer's men were more "motivated" for the visit of City.
"No, we were not lucky (to avoid defeat)," he said.
"I think it was a very close match and we had more options than Blackburn Rovers, more clear options, but we play against a very strong team here at home with lots of motivation.
"Disappointed? No. Of course everyone wants to win all the games but I repeat we played against a very strong team at home.
"I'm sure if Blackburn play the same way (in the Championship) they would maybe be in a different position in the table.
"It's normal (to have) motivation when they play against us."
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