It was a disappointing afternoon for Sahara Force India with both Sergio Perez and Nico Hulkenberg retiring from the United States Grand Prix.DNF Sergio Perez VJM07-02Tyre strategy: New Softs (1 lap)Sergio: “What happened today is really unfortunate. I made a move on Adrian [Sutil] at turn 15 when he left the door open, so I went up the inside. Then Adrian started to close the door and I had to try and brake later than him. By doing so I was unable to avoid contact with Kimi [Raikkonen], which caused me to make contact with Adrian also. I just didn’t expect Kimi to be in that position. It’s a big shame because I had a great chance to keep up my run of points finishes and I was determined to do well in such an important race. I feel very sorry for all my fans who came to support me this weekend and I’m disappointed I could not give them a race to remember.”DNF Nico Hulkenberg VJM07-04Tyre strategy: New Mediums (1 lap) - New Mediums (15 laps)Nico: “Unfortunately an early end to my race. I lost drive and had no more power so the team told me over the radio to stop the car. Even before that it had not been an easy race with a very difficult first lap. I was right behind Sergio and Adrian when they crashed, and Sergio’s front wing just happened to fall right in front of my car. I ran over it, which caused damage to my car and the tyres. I dived into the pits and lost quite a lot of track position. After that I was running behind the McLarens on a similar strategy with the plan to run the softs at the end of the race. It’s always disappointing to end a race with retirement but fortunately we have the next race in seven days so I will soon be back in the car. Sao Paulo is one of my favourite races and hopefully we can have a better weekend there.”Vijay Mallya, Team Principal & Managing Director“It was obviously a very disappointing day for Sahara Force India. We have had a pretty good level of reliability and consistency so far in the season, so when a day like this happens and two cars fail to finish the race it comes as a bit of a surprise. Checo's race was very short and it was a real shame as he was already up inside the points before his retirement. He had the pace to bring home a good result and perhaps it was just a case of being too eager to make up the positions. Nico had to pit as he couldn’t avoid the debris from the crash, but we are confident he would have been battling for the points. Unfortunately, he was sidelined by an engine failure that will be investigated once the power unit is back in the UK. Today's result complicates our battle for fifth in the Championship, but we will keep fighting until the very end. There are still two races, one with double points, and today has shown a bad weekend can happen to anyone."