2017 Formula One World Champion Lewis Hamilton said he was not concerned about his losses in the final two races of the season.Hamilton, who won nine races in the 2017 season to secure the title, failed to clinch the top podium finish in the Brazilian and Abu Dhabi Grand Prix. "I have zero concerns," the four-time Formula One World Champion was quoted saying by Sky Sports on Sunday."It is clear that something happens after you win the championship. All l can say is that the week after l won the championship I partied a lot. I celebrated because that is what you do. That definitely was not the case before the other races," Hamilton added. The 32-year-old finished the 2017 Formula One drivers standings with 363 points, above Ferrari's Sebastian Vettel (317) and Mercedes-AMG team-mate Valtteri Bottas (305).