The Finn drove alongside Massa for the Italian team from 2007 to 2009
Raikkonen will rejoin Ferrari next season, but the Spaniard believes that the ability of the car will determine how successful their season is.
"In terms of speed, Felipe is not any slower," Alonso told reporters.
"When they were together, Felipe was as quick as him in any way.
"So if we have a competitive car we will enjoy the season and do very good things. If not, it will be very similar to this year."
Alonso was speaking ahead of the Japanese Grand Prix, which takes place this weekend.