Mercedes team boss Toto Wolff expects the competition among Formula One's top teams to be closer in 2018 than it was in 2017.
Mercedes has won the last four drivers' and constructors' championships and enters 2018 as the favourites for both titles. However, after three seasons of utter domination between 2014 and 2016, the German manufacturer faced serious competition from Ferrari last year and only took control of the drivers' championship when Sebastian Vettel hit a run of reliability issues towards the end of the season.
Red Bull also emerged as a genuine challenger for race victories at the end of last season and Wolff expects at least three teams to be in the running for the championship in 2018.
"I think fans can look forward to a close competition," Wolff told the Mercedes website. "We had a rule change last year and we had three teams who fought hard at the front. The rules have stayed the same, the engines are converging and I think there are other teams expected to be racing at the front.
"McLaren with the Renault engine is going to be interesting, Renault will eventually recover -- they have put a lot of resource behind the project -- and Force India has been punching above their weight class. You can expect more with Checo [Perez] and Esteban [Ocon] being on fire, proving who is the quicker guy and Williams can always surprise. So, I expect there to be even more competition at the front this year between more drivers and more teams."
Asked if he has allowed himself to dream about the prospect of a fifth consecutive title, Wolff added: "No, because all points go back to zero. We are extremely happy and proud of the four double titles, but it isn't a guarantee of doing it a fifth time.
"The mind-set within the organisation is to stay humble about your own achievements but motivated and energised, in order to try and win races again and eventually - hopefully - be in the fight for the title."