Juan Pablo Montoya believes the reason Ferrari have struggled in recent years is because of the absence of Michael Schumacher.
The 38-year-old former McLaren driver and the seven-time World Champion were regularly fierce competitors during their time together in Formula, even though the Colombian seldom came out on top.
"The only time Ferrari did well was when Michael was there," he told German news agency DPA.
"We spoke once in the six years that we raced against each other.
"He was a competitor, not a friend. Formula one is very closed - as a McLaren driver I couldn't just go and sit in the Ferrari motor home."
Montoya also believes Mercedes was responsible for Schumacher's poor run of results when he came out of retirement to join the Brackley team.
"He didn't just forget how to drive. It's how it has always been in Formula One," Montoya insisted.
He added that he isn't particularly interested in F1 anymore and seldom spends time watching the sport.
"For seven years I have not watched Formula One, maybe one or two races a year," he admitted.
Any reproduction, publication or redistribution of this material without the written agreement of 365 Media Group is strictly forbidden.