Gasly started the campaign at Red Bull after being promoted from Toro Rosso to replace the departing Daniel Ricciardo. However, the French driver was completely outperformed by his team-mate Max Verstappen.
Alex Albon came in to replace Gasly at Red Bull, with the 23-year-old moving back to Toro Rosso, but the Frenchman has been driving "brilliantly" since being back at his former team.
Gasly recorded his first-ever podium finish on Sunday, shocking the F1 world by reaching the chequered flag in second-place, behind former team-mate Verstappen, in a hugely dramatic race in Brazil.
Vettel, who had to retire from the race due to being involved in a collision with his team-mate Charles Leclerc, has heaped the praise on Gasly for his drive on Sunday and his form since returning to Toro Rosso.
"I'm happy for him," Vettel said on Gasly to RaceFans. "Obviously I don't know the results, but I'm happy for him. I think he deserves it. I think he drove brilliantly since he got downgraded. I don't know what's the plan in the future with him."