Mark Schwarzer was signed by Chelsea as an experienced back-up for first-choice keeper Petr Cech - but the Aussie keeper committed a schoolboy error against Roma.
Chelsea fought back to win their final preseason tour match of America 2-1 on Saturday evening, but Schwarzer's howler took the headlines.
The Blues number two looked to control a routine back pass, but allowed the ball to roll across his body before it hit the post and back into the path of Erik Lamela.
The highly-rated Argentine winger slammed the ball home to hand Roma a 1-0 lead in the 20th minute.
Goals from Romelu Lukaku and Frank Lampard overturned the deficit though, resulting in a win that leaves Chelsea in good shape heading into the new Premier League season.
Unfortunately for Schwarzer, I doubt Cech will be suffering too many sleepless nights.
Check out the goal in the video below...