Red Bull's F1 switch of Verstappen and Kvyat 'difficult' for Sainz

When Red Bull demoted Daniil Kvyat to its junior team Toro Rosso after the Russian Grand Prix, it chose to promote Verstappen to partner Daniel Ricciardo.

Verstappen and Sainz made their grand prix debuts together at the start of the 2015 season, although Sainz entered F1 with more car racing experience.

Sainz was disappointed to not replace Kvyat and used that to motivate himself and deliver a strong season, finishing sixth in the next grand prix, his home race at Barcelona, which he followed with points finishes in Monaco and Montreal.

By mid-year, he had secured a Toro Rosso contract extension for 2017, and the Spaniard also finished sixth at Austin and Interlagos before the end of the season.

"I tried to show a lot of strength but it was a difficult moment, obviously, because you don't like being overlooked by someone," Sainz told Autosport.

"People talked about how difficult it was for Kyvat but people thought it was easy for me also.

"They didn't take into account that it was also a difficult moment for me, that I had to react and I had to suddenly take the attention of Red Bull.

"I said to myself, 'I will prove you wrong' and then my best three races in Formula 1 came directly after that and a contract arrived in Baku and I signed it immediately.

"So it was a big turning point and a good reaction to a very tricky situation.

"It would have been quite tricky for me suddenly to do not such a good job against Kyvat.

"It could have put my F1 career in a tricky situation so I was under a lot of pressure and I performed at my best level."

Sainz said the turn of events heaped the pressure on but he reacted well, outperforming Kvyat to achieve a points tally nearly double that of the Russian on his way to 15th in the championship.

"I remember when this happened, I was going to Barcelona, it was my home race," said Sainz.

"There was pressure from the change of team-mate and it was nearly obligatory for me to be ahead.

"I was under a lot of pressure but suddenly everything went perfect from then onwards in the season so it was a good moment and something that I'm very proud of."