Nico Hulkenberg felt the slow puncture that cost him sixth place in the closing stages of the Korean Grand Prix was cruel luck given how strong his performance had been at Yeongam.
Williams was on course for fifth and sixth places with Rubens Barrichello and Hulkenberg going into the final laps, but heavy tyre wear saw the former fall to seventh, while Hulkenberg's extra pit stop meant he could only salvage 10th.
"We did everything right today; we simply had some bad luck," said Hulkenberg. "I came in just before the safety car was released which cost me time and lost me a place. We managed to claw back position and were running in sixth towards the end of the race, but then my engineer told me I had a slow puncture.
"I couldn't keep running until the end as the car was totally undriveable. We had to pit and that cost us a big result today."
Barrichello was pleased with Williams's pace even though the result was less than the team had looked set for.
"It was a tough race, but we were competitive today," said the Brazilian. "I was lucky with the timing of the safety car and we were running in a good position right up until the closing stages. Unfortunately, I just ran out of tire in the last five laps, which cost us two places in the end."