In the third minute of extra time during the game between Real Madrid and Bayern Munich, the ITV1 HD channel switched to ITV newsreader Mark Austin as he prepared for the evening's News at Ten.
For about 15 seconds, viewers saw Austin standing in a news studio, adjusting his jacket buttons and looking into the distance.
ITV's commentator apologised on air for the error, which a spokesman for the broadcaster later said was down to "technical fault".
"We would like to apologise for this interruption to the game," the spokesman added, confirming that it only affected viewers in London and the south-east.
After the incident, Austin tweeted: "Button tending is an underrated habit."
This is the latest in a series of errors during ITV's football coverage, including an embarrassing situation during the 2010 World Cup.
Instead of seeing Steven Gerrard's opening goal for England at the tournament, some 1.5m ITV1 HD viewers instead saw an advert for a car.
The situation resulted in more than 800 complaints to Ofcom, although ITV was later cleared by the media regulator over what was deemed an "unfortunate" mistake.
A year earlier, ITV viewers missed out on the winning goal in an FA Cup tie between Liverpool and Everton, after the channel also switched to an advert.
Watch Mark Austin interrupt the football below: