Fernando Alonso believes former team-mate Felipe Massa will be a "strong rival" this season.
Massa spent eight years at Ferrari - four of which as Alonso's team-mate - but moved to Williams at the end of the 2013 season after he was replaced at the Maranello team by Kimi Raikkonen.
The Brazilian's move to Williams was seen by some as a backwards step for the 11-time race winner, but during pre-season the Grove outfit shocked many with their pace and reliability and has emerged as one of the favourites to win the season's first Grand Prix in Australia.
"I've talked with Felipe several times this year already," Spaniard Alonso is quoted by Brazilian publication Globo.
"He is happy, Williams has so much history in formula one and is not just any team, and they have had a very strong pre-season.
"It is very positive because now they can be fighting. Felipe will definitely be a strong rival this year."
Two-time Drivers' Championship winner Alonso also downplayed suggestions that he would struggle to form a partnership with Raikkonen, himself a former World Champion.
"We are trying to work together, working for Ferrari and arriving in Australia to fight for the race," Alonso added.
"So let's have this internal competition - normal in every team - because we all want to be ahead of the other one, and hopefully this can help Ferrari."