George Russell says he will not be concerned about trailing in the drivers’ championship until the summer break. The Mercedes driver won the opening race of the season in Melbourne and was widely expected to dominate the early part of the season in the grid’s leading car. But his 19-year-old team-mate Kimi Antonelli has ripped up the script with back-to-back wins in China and Japan to lead the standings by nine points. The season resumes after a five-week break, enforced by the cancellation of April’s races in Bahrain and Saudi Arabia, with Mercedes still expected to lead the way in Miami . But Antonelli’s form has raised the prospect of the young Italian taking the title fight to his experienced team-mate. Russell said he was not worried about being behind at this point, comparing this stage of the title race to the opening few miles of a marathon. “Nobody remembers who leads the standings for the longest time,” Russell said.…