Daniel Ricciardo says team-mate Daniil Kvyat deserves praise for turning around a tough start to his time at Red Bull Racing, adding that he has still much 'room for growth'.

The Russian youngster, who made his F1 debut in 2014 with Toro Rosso, was promoted to a Red Bull Racing drive for 2015 in place of the Ferrari-bound Sebastian Vettel, but a combination of factors - both technical and self-inflicted - left him on the back foot initially.

However, following a breakthrough run to fourth position at the Monaco Grand Prix, Kvyat's form snowballed over the course of the year, peaking with a maiden podium in Hungary, while he was also in contention for a similar result in Mexico and challenged for the race lead in the United States.

Going on to finish ahead of more experienced team-mate Ricciardo in the overall standings, the three-time race winner was impressed with Kvyat's reaction to such a difficult opening few races.

"He [Kvyat] has shown speed, I can't say he is not quick," he said. "He has some good qualifying and races, so throughout the season he is showing some signs. I think what was probably surprising or good from him was the first four or five races, it seemed he wasn't quite up to speed, whether it was with a bigger team or the new car, it looked like he would either learn quick or it would be a disaster of a season for him. He turned it around quickly."

Though Ricciardo plays down the deficit to Kvyat at the end of the year - pointing out he suffered more technical-related non-scores -, he nonetheless predicts there is plenty more to come from the former GP3 Series champion.

"He has maintained a pretty good level of performances. We can work who had DNFs [laughs], but he has done well. I think he has adapted well, picked himself up when he had to and he is still young so there is room for improvement and growth. I think he is more comfortable with the world of F1."

Ricciardo will again be partnered with Kvyat for the 2016 F1 season driving a Red Bull powered by TAG Heuer-branded Renault engines.