be pipped to the post
To be defeated or overcome by someone by a very narrow margin or at the final, crucial moment, especially in a race, competition, or athletic event. Primarily heard in UK, Australia, Ireland. The favoured runner held the lead for the majority of the race, but he was pipped to the post by a relatively unknown competitor in the final 100 metres. It appears the current MP has been pipped to the post, being narrowly defeated by the youngest person to ever serve in parliament.