F1: Fernando Alonso braves back pain for Ferrari in the United States

Fernando Alonso has admitted defeat in the race for the 2013 Formula One drivers' championship (GETTY IMAGES)

Ferrari's Fernando Alonso will compete in this weekend's United States Grand Prix despite ongoing back pain.

The 32-year-old has been taking anti-inflammatory tablets but Alonso said on Twitter: "Packing the bag for Austin, with some pain, but eager and confident to help the team."