The Nerazzuri bowed out on away goals after a 4-1 win at the San Siro saw the tie squared at 4-4 on aggregate.
However, the Argentine said that his teammates are happy with their efforts.
"This is what makes football so wonderful – we must always believe," Football Italia quotes the 39-year-old as saying. "Nobody expected us to put four goals past Tottenham.
"We are happy with the performance and the way we interpreted the match. Unfortunately, we are still out of the Europa League.
"We must take many positives from this match."
Inter face Sampdoria at the Stadio Luigi Ferraris on Sunday night.