Bruno Senna has blamed his failure to make Q2 for the third time this season on a lack of meaningful practice time.
The Brazilian sat out first practice in Korea in favor of reserve driver Valtteri Bottas and his Saturday morning practice running was compromised by a front wing problem despite completing 18 laps.
"It's a typical result of losing the first session on Friday, then having an OK second session but a bad third session with technical problems," he said when asked what went wrong.
"When you lose a session and then lose another session because of problems, that's it. On a tight grid like this, you don't have a half-second margin to play around with.
"I'm not surprised that we had a struggle after the morning session when we were chasing front wing problems and not really working on setup."
Senna described his Q2 lap as "OK" but setup shortcomings caused by his practice problems restricted the potential of the car. Although teammate Pastor Maldonado was four tenths of a second faster than him, Senna believes that the setup problems were to blame for the gap.
"We made some decision on car setup in the afternoon and went the wrong way, which is understandable," he said. "The result is where we are in qualifying. We are not particularly quick anyway, but it looks worse than it is."
Senna did attempt a second flying lap on his second run in Q2. He would have bumped McLaren driver Lewis Hamilton had he been able to match Maldonado's time.
"I improved a little bit in the first sector, but by the halfway point of the lap the tires had given up already. It's a one-lap tyre and [the track is] very hard on the tires with he long corners. I needed to try another lap because I knew that it wasn't good enough but it didn't happen."