The Mercedes gets affected by following another car more than most, and the Red Bull happened to have a driver who is known to be happy to risk knocking the other driver off the road - Lewis openly admitted he was extremely cautious, which he wouldn't have been for anyone else.

Thankfully there are big plans in place to avoid the airflow issues of following another car (overseen by Ross Brawn, the technical guy at Ferrari during Schumi's reign, and the nominal owner of the Brawn team), but the full thing can't be brought in until 2021 due to contracts... but they are making some changes for next year, which the teams reckon will improve things.