(Reuters) - Championship leader Lewis Hamilton returned Mercedes to the top of the Formula One timesheets in Saturday's final practice for the Belgian Grand Prix, while Sebastian Vettel ended the session in last place on a weekend that continued to get worse for Ferrari.
The Briton, who had ended Friday in third behind Renault's Daniel Ricciardo and Red Bull pace setter Max Verstappen, vaulted to the top with a time of one minute 43.255 seconds on a cool afternoon at the Spa-Francorchamps circuit.
That put him 0.230 seconds clear of Frenchman Esteban Ocon who replaced team mate Ricciardo in second as Renault continued to show promise.
Briton Lando Norris, who has a Belgian mother and spent his Christmas holidays in the country, was third for McLaren.
Struggling Ferrari, lacking speed in a straight line, were not expecting a repeat of last year's dominant display at the high-speed Spa-Francorchamps track when Monegasque Charles Leclerc scored his maiden Formula One win from pole position but their lack of pace this year was still remarkable.
Leclerc could do no better than 17th while four-times champion Vettel, who is leaving Ferrari at the end of this year and faces an uncertain future, propped up the timesheets in 20th.
The pair were among several drivers hampered by slower cars as the entire field bunched up in preparation for their final timed laps. The Italian team faced the prospect of neither of their two cars making it past the first phase of qualifying later on Saturday.
Leclerc and Vettel had ended Friday in 15th and 17th respectively.
Red Bull's Alexander Albon was fourth on Saturday, ahead of Valtteri Bottas in fifth for Mercedes.
Finn Bottas, who celebrated his 31st birthday on Friday, had been fastest in the first session of practice but suffered a lock-up and a slide on what should have been his fastest lap during Saturday's final session.
Friday pace-setter Verstappen, also hampered by slower cars, was sixth, ahead of Ricciardo, with Lance Stroll eighth for Racing Point.
Carlos Sainz took ninth for McLaren ahead of Sergio Perez in the other Racing Point.
Saturday's session, which started in overcast conditions that later turned sunny, was uneventful.
Haas drivers Kevin Magnussen and Romain Grosjean were out early, putting in the laps as they made up for lost time after engine problems limited running for them on Friday. They were 14th and 15th respectively.
Hamilton, winner of four of this season's six races, leads Verstappen by 37 points in the overall standings with 11 of this season's 17 races still to run.
(Reporting by Abhishek Takle in Mumbai; editing by Clare Fallon)