SEPANG • Disappointed Mercedes team principal Toto Wolff described his team's woeful performance in practice for the Malaysian Grand Prix as "the worst Friday I can remember".
The Austrian was vocal after Formula One championship leader Lewis Hamilton and Valtteri Bottas could manage only sixth and seventh fastest respectively in both of yesterday's practice runs.
"Whether it was in the wet, the dry, long runs or single lap, we lacked pace," Wolff said. "We only have 12 hours to get it right."
To make matters worse, Sebastian Vettel, who lies 28 points behind Hamilton in the race for the drivers' title, smashed the Sepang lap record in his Ferrari, lapping more than 1.4 seconds quicker than the Mercedes.
"The lap time is reality. The lap time showed we are not quick enough. It is one of the worst Fridays I can remember," said Wolff.
Vettel clocked 1min 31.261sec around the 5.543km circuit to smash the old mark of 1:32.50 set by Fernando Alonso in 2005.
Vettel's team-mate Kimi Raikkonen was second quickest, six-tenths of a second adrift.
"It's been a decent day," Vettel told Sky TV. "Fridays are when you play around and try some things. It looked like both Mercedes were struggling in morning and afternoon, so I'm pretty sure they will be fine tomorrow."
The Red Bulls of Daniel Ricciardo and Max Verstappen came next and even the McLaren of Alonso, which has been poorly paced all season, was fifth in the afternoon after being third fastest in the wet first session. "I think Mercedes were quite heavy today. I don't know if it's legit or they're playing some games," said Ricciardo.
Hamilton sat in the garage for most of the morning as the rain swept across the circuit. And the three-time world champion was on just his 10th lap of the afternoon when he took too much speed into Turn 8, resulting in a sideways excursion into the gravel.
"It's been a very difficult day," he said. "I've been struggling with the car, so we have to review and try to understand where we have gone wrong with the balance."
Bottas was optimistic the team could have a better Saturday.
"We're definitely lacking some performance, and it seems like Ferrari and Red Bull are very strong," said the Finn. "So we have some work to do if we want to be on the front row tomorrow. The key area we are going to need to focus on tonight will be getting the maximum out of the tyres over one lap."
The morning practice was shortened by rain and in the afternoon, when the cars could run on slick tyres, the session ended 20 minutes early when Romain Grosjean hit a loose drain cover, which should have been welded down securely.
The Frenchman's rear right tyre was ripped off in a frightening explosion at Turn 9, throwing his Haas into the barriers at high speed and bringing out the red flag.
"I'm all right, I didn't see anything," said Grosjean. "The next thing I knew was that the car was not there any more. It was just spinning and heading for the wall."
Formula One officials immediately launched an inspection of every drain cover at the circuit.
"Hopefully they check all the drains," Ricciardo said. "Because you do not want to think about it in the race. Some corners, you really need to use the kerbs to let the corner flow and to use the momentum flow. So hopefully they fix it all."
F1 MALAYSIAN GP Practice 3 & qualifying
Singtel TV Ch114 & StarHub Ch208, 1.55pm & 4.30pm