Sky didn’t have a line-up picture for Liverpool’s Trent Alexander-Arnold so had to improvise

Trent Alexander-Arnold was the surprise starter for Liverpool in today's big clash with Manchester United.

It was such a surprise that Sky Sports were caught out by not having a line-up picture for the Reds youngster, who stepped in to replace Nathaniel Clyne at right back. Our eagle-eyed chief football writer Tony Barrett was among those to spot it... https://twitter.com/tonybarrett/status/820661714215702528 And here's a closer look... https://twitter.com/RealTlkFootball/status/820664703701684226 The giveaway is of course the number on the shorts, with Joe Gomez wearing the number 12 clearly visible in the pics above, when Alexander-Arnold currently wears number 66. [caption id="attachment_107525" align="alignnone" width="1024"] Trent Alexander-Arnold wears number 66 - not number 12 (Photo by Laurence Griffiths/Getty Images)[/caption]   Although the clash at Old Trafford was the 18-year-old's first Premier League start, he has played four times already this season, twice in the EFL Cup, once in the FA Cup and in the Premier League away at Middlesbrough. Time to get a real one sorted, Sky... Catch up with this week's episode of 888sport Football Friday Live: