In wet conditions, Ricciardo qualified second for Sunday's Chinese Grand Prix, well off the pace of the supreme Lewis Hamilton, but ahead of Vettel for a third time this season.
Ricciardo's impressive form has been stunted by incidents beyond his control including penalties for a fuel-flow irregularity in Australia and a botched pit-stop in Malaysia.
And Vettel knows he cannot rest on the glories of the previous four seasons, which have seen him crowned world champion, as Ricciardo looks to make a splash at Red Bull.
"This year is very, very different, the cars are different, you cannot compare last year to this year," Vettel said.
"Daniel is doing a very good job. He has not had one good weekend, he has (regularly) had good weekends.
"So far he is able to get the maximum out of the car, and on my side, maybe I am struggling a bit more.
"But at the end we have the same car so if he beats me he beats me fair and square. That is not to my liking. Equally I know I have to do a little bit better."
Hamilton's efforts were enough too see him break Jim Clark's British record for F1 poles as he recorded the 34th of his career more than half a second clear of the field.
Ahead of Sunday, which will see him head the grid for the third race in a row, Hamilton was delighted with his dominant showing, but remains wary of a renewed fight from Red Bull if the wet weather returns.
He said: "Definitely the most satisfaction is getting this result when it is raining.
"It was so slippery out there, trying to find the grip and not make mistakes. It was a tough session, but the car was feeling great.
"There are some things that can be improved on but it has put us in a good position for the race.
"I hope it is a dry race, I'd see these guys (Ricciardo and Vettel) a little closer in the wet."