As if Liverpool didn't have enough on their plate with fierce rivals Manchester United coming to town for a first-ever European showdown, they'll have to walk a fine line between passion and control if they want to escape with an advantage in both goals and players.
UEFA appointed Spanish referee Carlos Velasco Carballo to officiate the game between England's top two sides and fierce rivals. Carballo has been one of the most card-happy refs in Europe this campaign, issuing 10 red cards since the start of the season. In his last game out, a 3-3 draw between Deportivo and Malaga, he issued 8 yellows and a red.
Obviously this poses an additional challenge for both English sides tonight. English refs, generally speaking, are more likely to adapt a "let 'em play" approach than their continental counterparts. Regardless, like any derby, this one has seen more than its fair share of cards and sending offs over the years, the last of which needs no mention.
This weekend, both sides had players sent off--Juan Mata for United and James Milner for Liverpool--although their disciplinary records are fairly average by Premier League standards. Manchester United has received 51 yellows and 1 sending off in league play, compared to 47 yellows and 2 reds for Liverpool.
Carballo is just another twist to watch out for tonight, one that could have major implications for this game and beyond.