But, with Red Bull traditionally using Toro Rosso as a driver development team, undoubtedly next in line for a Faenza-made cockpit is da Costa.
The 21-year-old has been singled out as a potential champion in this year's Formula Renault 3.5 series.
After that, the next logical step for Felix da Costa would be Toro Rosso.
"I'm not too worried," Vergne is quoted by Brazil's Totalrace.
"I am confident that I will have the performance. We definitely have a better car this year compared to last year, and also I'm a better driver, more experienced, and that combination automatically gives you better results."
As for Felix da Costa's likely candidature for a Toro Rosso seat in 2014, Vergne answered: "I see no problems with that. That's how it works at Red Bull.
"I've been in the same position. Antonio is a good driver.
"If he keeps doing a good job, he deserves to be in F1 and, following the policy of Red Bull, if one of us - me or Daniel - is good enough to be in the first team (Red Bull Racing), that will leave a free seat at Toro Rosso," he added.