Red Bull's Sebastian Vettel rued a "very frustrating" Malaysian Grand Prix after a stormy weekend left the reigning world champion trailing in this season's standings on Sunday.
Vettel, starting from fifth, battled through the chaotic, rain-hit grand prix but was hit by a radio breakdown and then a puncture in the dying laps, leaving him out of the points.
Vettel, who is looking to seal only Formula One's third hat-trick of consecutive championships, is now sixth in the overall standings after the first two rounds. Fernando Alonso won Sunday's race.
"Most crucially we lost radio communication, and that makes it very difficult in these conditions to know what's going on. Nonetheless we did our maximum today and got up to fourth," Vettel said.
"To then lose the race how I did is very frustrating. Some people need to look more where they are going," he said, referring to Narain Karthikeyan's late collision which exploded his back tyre.
"Today it was crucial to come in at the right time. Having no radio meant we were delayed getting the messages, and I didn't hear anything from the team at the end," he added.
Red Bull's principal Christian Horner said it was hard to draw conclusions from the race, dismissing it as "quite peculiar."
Vettel's team-mate Mark Webber finished fourth on Sunday and lies fourth overall.
"Looking at today's performance, one would have to say that Sergio Perez is currently the top favourite," Horner told reporters.
"Today was quite peculiar because if you look at it Sergio Perez was the quickest car on track. He was catching a Ferrari... and pulling away from a McLaren," he added.
"It's difficult to draw too much out of the first couple of races... We know we have got things that we can improve on, and that's what we'll be focused on for China. But it's fairly unpredictable at the moment."
He said the strategy to bring Webber in for an early pit stop ahead of the field had been right, but the Australian was unlucky as many others followed him, causing him to get stuck in the pit lane.
Meanwhile, Vettel's car faced multiple problems, including when the onboard radio broke and the team lost communication with him around lap 20.
Later, Vettel's left back tyre punctured and damaged the braking system, prompting frantic - and unheard - radio calls for the German to stop racing for safety reasons. However, Vettel brought the car home unscathed.
"We tried and tried on the radio but obviously he wasn't picking up on the radio. Thankfully the car did get to the end without the left rear brake failing," Horner said.
"That (puncture) was frustrating for Sebastian because for sure at least a fourth-place finish was on for him today."