UEFA announced on their website that Martin Atkinson will be the referee in charge of Real Madrid's first Semifinals leg against Juventus in Italy this Tuesday.
OFFICIAL | Martin Atkinson is your referee for the UEFA Champions League Semifinals First Leg between Juventus and Real Madrid.— Lucas Navarrete (@LucasNavarreteM) May 3, 2015
As a British referee, Atkinson likes to let play on. He officiated Real Madrid's 0-2 win against Schalke 04 in the Round of 16 too, a game in which he didn't have problems or controversy. Still, Martin Atkinson likes to keep things under control and shows a fair amount of cards to achieve that.
He was also in charge of Juventus' 3-2 win against Olympiakos in this edition of the Champions League, and most recently he also officiated Bayern Munich's 6-1 win against Porto, a victory that sealed Bayern's presence in the Semifinals draw of this Champions League edition.