win by a mile

To win (something) by a very large distance or wide margin. A noun or pronoun can be used between "win" and "by." Everyone thought it would be a close game, but with a 45-point lead heading into the last two minutes, it looks like the underdogs are going to win it by a mile. Her candidacy seemed like a long shot from the very beginning, but she kept growing in popularity leading up to the election and ended up winning by a mile.