Formula One leader Lewis Hamilton had the fastest time in practice for the inaugural Russian Grand Prix on Friday, while drivers and teams showed their support for injured colleague Jules Bianchi.
Hamilton was second in the morning session behind Mercedes teammate Nico Rosberg but dominated the afternoon run by a wide margin. Rosberg dropped to fourth.
Kevin Magnussen of McLaren was second, with Ferrari driver Fernando Alonso third. Valtterri Bottas of Williams was fifth behind Rosberg, and Jenson Button in the second McLaren completed the top six.
The Marussia team ran only one car in respect to Bianchi, who remained in critical condition with severe head injuries after crashing into a mobile crane at the Japanese GP last Sunday.
Marussia president Graeme Lowdown said it was a difficult decision to run only one car, especially since the team was ninth in the constructors' standings.
"We are largely in that position because of Jules, and as a racing driver he'd want us racing," Lowdon said.
Hamilton's fastest lap of 1 minute, 39.630 seconds on the Sochi Autodrom, built around the Olympic Park that was used for the Winter Games in February, was an improvement of nearly three seconds from his morning run on the unfamiliar circuit making its debut on the F1 calendar. He was nearly a second ahead of Magnussen.
"I like the new circuit. It's got really good grip and great corners, with a lot at medium speed," Hamilton said. "It's good fun. The car has been feeling really good today."
Mercedes can clinch its first constructors' title with a victory in Sunday's race. Hamilton leads Rosberg by 10 points in the drivers' standings.
Hamilton's promising practice time makes him a clear favorite to win his ninth race of the season and close in on the title, with three races remaining after Sunday's contest.
Hamilton was .864 seconds ahead of Magnussen. Alonso was .874 seconds behind and Rosberg was .912 adrift.
Bianchi's father, Philippe, told the newspaper Nice Matin that "Jules is fighting as he always did, the same way as if he was racing. He is strong."
With the French driver's car in the garage in pit lane, Marussia's other driver, Max Chilton, placed next-to-last.
"It is going to be a very emotional weekend for the whole team, but we will try to get through it and keep praying for Jules," Chilton said.
Alonso's car bore a sign saying "Forza Jules" (Go Jules), while other drivers had a sticker on their helmets saying in French, "Tous avec Jules" (Everybody with Jules).
Sebastian Vettel, who was ninth in practice, said getting back to driving "does and doesn't help" dealing with Bianchi's situation.
"It helps to get your head elsewhere and focus on the day job ... it keeps you occupied. But on the other hand, it's only been a couple of days, so it's quite fresh and difficult," Vettel said.
Vettel's Red Bull teammate, Daniel Ricciardo, the only driver with a realistic chance of challenging the Mercedes pair for the title, finished 12th after his car stopped on the track, producing a red flag late in the session.