Sebastian Vettel won four consecutive world titles between 2010 and 2013 but since moving to Ferrari has failed to compete with Mercedes as they are on a streak of five straight Championships. Max Verstappen meanwhile has had far less success in terms of titles up until now but at 21-years-old still has much to learn and is expected one day be the leading force in the sport.
Ricciardo has driven as a teammate with both drivers and he admitted he thinks Verstappen has much more room to get faster than Vettel does.
"I won’t take anything away from Seb, he is not slow by any means," Ricciardo said as quoted by F1i.com.
"Probably as well because Max is still young, and if he’s quick now, he’s probably only going to get quicker.
"Seb has been doing it that long, I think you always improve as a driver, but there’s less room for him to grow, and more for Max.
"If Seb’s listening, sorry Seb! You’re still a badass, it’s alright," Ricciardo joked.