Maguire won gold in a time of 3.11.83 – narrowly ahead of his team-mate Daniel Sidbury who set the pace before being hunted down.
“It was pretty crazy. We started off pretty quick,” Maguire said.
“Kudos for Danny for taking it out. But he made a gap and we had to chase him down.
“Then I knew I had a little bit left for the home straight, so I thought I would give it a go.”
Australia’s Samuel Carter won bronze, with the trio well clear of the rest of the field.