Lewis Hamilton has acknowledged his battles with Sebastian Vettel for the Formula One world championship as the greatest so far in his career. The world champion, speaking before this weekend’s Emilia Romagna Grand Prix at Imola, described his previous battles with Vettel as draining. In 2017 and 2018 Hamilton and Vettel, who was then driving for Ferrari, were in a closely fought contest for the championship. In both years Ferrari enjoyed a quicker car for at least half the season during which Vettel enjoyed an early lead on points, but Mercedes and Hamilton turned it around and ultimately won the championships. The pair developed a strong mutual respect in a hard but fairly contested fight. “Mine and Seb’s battle were my favourite so far,” Hamilton said. “It’s knowing I was racing against an incredible driver, not only that but a great man in Seb who is a four-time world champion and we were racing against another team, he was at Ferrari who were very strong at the time. It took a lot out of both of us in that period of time, to remain focused to deliver weekend in, weekend out. That was a difficult period for us and it brought us closer, because the respect we have between us is huge.” Hamilton is attempting to secure a record eighth drivers’ championship this year. The 36-year-old Briton won the opening round in Bahrain – Vettel, now at Aston Martin, was down in 15th – but it was a victory very much against the odds. Red Bull had the better pace at the Sakhir circuit and Max Verstappen was formidably quick but Mercedes pulled off a tactical coup, gaining track position through the stops and allowing Hamilton to go on to defend his lead with great skill. This is the first time Verstappen has had the car to mount a serious championship challenge and go toe-to-toe with Hamilton, who accepted he was likely once more to face a stern test and one that might yet turn into a classic rivalry. “It’s different now if I am racing with Max, he doesn’t have the background that Seb has but he has the chance to be a future champion,” Hamilton said. “Whether that is now or later depends on the job ultimately that the team and I do. “I can’t guess what is ahead, it’s exciting for the fans and I hope that it’s all that it’s cracked up to be. We need the best entertainment possible for the fans, we just want to be fighting with the best drivers.” The narrow track of the Autodromo Internazionale Enzo e Dino Ferrari will make overtaking tricky lending particular significance to qualifying this weekend, where Red Bull can expect to have maintained their advantage over Mercedes. Toto Wolff, the Mercedes team principal, said: “We may have won the first round, but we’re under no illusions that this will be a straightforward season. The car is still lacking pace over a single lap and Red Bull appear to have the edge right now.”