One of the most notable aspects of football is that it's such an unpredictable sport. When Petr Cech signed for Arsenal, many people were heard saying that he would be the difference in a title challenge for the side. Unfortunately, he made a difference against West Ham, but not for good reasons. Few could have penned a worse script for the Czech stopper, who looked off the pace and average in this London derby. Misjudging a Hammers free kick terribly, Cech was nowhere to be found as Cheikhou Kouyate headed into an empty Arsenal goal for the opener on 43 minutes. Worse, he seemed to misjudge again on 57 minutes, going the wrong way initially when trying to save a Mauro Zarate shot. As far as debuts go, this was one to forget for the former Chelsea keeper. Surely things can only get better for the big man in weeks and months to come, because this was a complete disaster. Goalkeeper has been a tough position for The Gunners over the years, but they really thought they'd sorted that out by signing Cech. Maybe they have, but not at the weekend. What other big losers can you think of from the opening weekend of the Premier League? Do you agree with the choices listed here? Let us know your thoughts down in the comments section below!