Franz Tost has warned Daniel Ricciardo that he faces a tough task should he be called up to partner Sebastian Vettel next season.
With Mark Webber retiring from F1 at the end of this season, the race is on to take the Aussie's Red Bull seat.
And although 2007 World Champion Kimi Raikkonen is in the running, Toro Rosso's Ricciardo has emerged as the favourite.
Asked whether Ricciardo will make the move, his team boss Tost told the official F1 website: "The likelihood is pretty high.
"Red Bull Racing is showing interest in Daniel and the decision will be made inside Red Bull. So there is no decision yet - but my understanding right now is that it could, in fact, be Daniel."
Should the 24-year-old step up he can expect a massive fight on his hands as his new team-mate is not only a three-time Champ but will also be the new kid at a team where Vettel is very much top dog.
"He has to bring a lot to the table, that's for sure," Tost added. "Let's have a look at Seb: he's a three-time Champion - at least per today - which indicates his huge talent.
"He's also extremely disciplined; he's got a sharp technical understanding - probably one of the best in the paddock; he can fight ferociously - he's proven that time and again; and he is established in a winning team that he has built up with.
"Remember: when Seb left Toro Rosso to join Red Bull Racing, the team was in no way the winner that it is today - Seb has contributed a lot to make it happen.
"So if you want to be the new kid on the block you better have all these facts in mind - and show even more commitment to come at least close to Seb. That will be a rough ride!"
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