Andretti, who won the championship with Lotus in 1978, drove for Ferrari in 1971, 1972 and 1982 and thinks that Vettel is keen to emulate hero Michael Schumacher - who took five titles during an 11 year spell at Ferrari.
"I would love to see Vettel win a championship with Ferrari because I think he really wants to be there," Andretti told ESPN. "He’s there because it has been his dream, I think Michael [Schumacher] was his hero."
"He’s a bit frustrated obviously because things are the way they are at the moment. I think he gets on very well with Kimi, which is important as a team. But he’s showing his frustration a bit, you can tell, because he just feels that it could be better."
"He belongs there and I think pretty much everyone would like to see him be successful with Ferrari. I’m one of those, I’m a fan of his in every way. He expressed that to me [that he wants to win with Ferrari] a long time ago when he was first coming into the ranks of Formula One that that’s what he’d like to be and I think he’s where he wants to be."
Bahrain International Circuit - Winter testing