Derry had four players yellow carded under the experimental rules during Sunday's 1-9 to 0-10 win over Mayo, much to the annoyance of manager Damien Cassidy. The new rules meant Cassidy had to replace Barry McGuigan, Patsy Bradley, Brian Og McAlary and Ryan Dillon during the game. "Obviously I'm disappointed that we ended up getting four players sent off," the new Derry boss said. "A couple of the sendings off, I couldn't really argue with to be honest, but the counter of that is how did Mayo not manage to get a player sent off? "I can certainly see two tackles in particular that stand out in my mind as obvious yellow cards and they weren't implemented, but it's done and dusted. "The game's over. We've managed to come through it, even with those circumstances that we were faced with and I just think the rules are going to bring more trouble than they're worth before the League is finished. "The fun of it all will come together when we come down to the last two or three games, when the relegation battles are starting to be big strong issues and that's when there'll be a lot more fun around the whole issue." Mayo boss John O'Mahony was more concerned with his team's defeat and said, "It is disappointing to lose the game. I thought when we got level after they got the goal that we could have kicked on from there."