Madrid, thanks to Gareth Bale, a Juan Gongora own goal and Brahim Diaz's late individual effort, eventually won 3-1 at the tiny Las Pistas stadium, where 4,000 supporters of a club that has only existed since 2013 saw their side go head to head with the 13-time European champions.

Yet Romero's stunning effort after 57 minutes will live far longer in the memory than the goals that won the day for Madrid.

The substitute had been on the field barely a minute when he ran from just inside Madrid's half to the edge of the penalty area before curling a fine left-footed finish out of the reach of Alphonse Areola.

That brought Unionistas level, following Bale's first-half effort, but parity was all too brief, with the 62nd-minute own goal and Diaz's neat stoppage-time finish deciding the day, the Segunda B minnows just edged out by their millionaire visitors.