Kimi Raikkonen led the way in final practice for the Spanish Grand Prix as Ferrari showed signs of challenging Lewis Hamilton's Mercedes team.
Hamilton was fastest in both practice sessions on Friday, but the British driver was only third quickest on Saturday morning as Raikkonen headed a Ferrari one-two from championship leader Sebastian Vettel.
Raikkonen's best effort of one minute and 20.214 was 0.242 sec quicker than Vettel with Hamilton nearly four tenths slower.
Valtteri Bottas's Mercedes team broke the Friday night curfew to fix an electrical fault on his car. But when they put Bottas's engine back together another problem was discovered in the form of a water leak.
Bottas's Mercedes' mechanics faced a race against time to get the Finnish driver on track for the one-hour session, but with a little more than eight minutes remaining he emerged from the garage.
The 27-year-old posted the fourth best time, albeit 0.654 sec slower than Raikkonen's best effort.
McLaren's awful season descended into further chaos on Friday when Fernando Alonso broke down having negotiated just three corners on his initial outing.
But the double world champion will be somewhat heartened by his trouble-free morning on Saturday where he finished a credible 10th in the order, and within two seconds of the front runners.
Last year's winner Max Verstappen finished fifth ahead of his Red Bull team-mate Daniel Ricciardo.
Briton's Jolyon Palmer, in need of a good weekend following his troubles this season, was eighth fastest in practice on Friday, but was only 18th of the 20 runners this morning.