P3: Bottas heads Hamilton
Valtteri Bottas and Felipe Massa demonstrated Williams' pace in final practice for the Austrian GP by sandwiching Lewis Hamilton at the top of the timesheets.
A lap of 1:09.848 from Bottas in the closing moments on Saturday morning saw the Finn go 0.050s faster than Hamilton, who had set the pace at the 4.320km track on Friday afternoon.
Massa in turn was just 0.003s slower than the Mercedes driver in third place, setting up the possibility that Williams might repeat their strong showing at the Canadian GP two weeks ago.
With Hamilton and Mercedes team-mate Nico Rosberg suffering poor reliability in Montreal, Massa at one point appeared a likely winner at Circuit Gilles Villeneuve.
Tyre strategy and the Brazilian's spectacular last-lap collision with Sergio Perez eventually intervened but former Williams World Champion Damon Hill thinks they have another chance this weekend.
"I think it's a statement of intent," he told Sky Sports F1. "It's definitely a consistent performance we have seen over the last two days. I still think Mercedes and Hamilton are looking very strong, but Williams look even more competitive here than they did in Canada."
Bottas and Massa were respectively fourth and fifth fastest in P2, albeit almost a second off Hamilton's pace, suggesting that the runaway championship leaders were running their cars with more fuel this time around.
The Williams pair also ran one-two earlier in Saturday's session on the prime tyre, although questions were asked on Friday about how the FW36 might cope with tyre wear this weekend.
Rosberg, who currently leads Hamilton by 22 points in the drivers' standings, was fifth fastest after Toro Rosso's Daniil Kvyat also put in a fast lap as the chequered flag fell.
With the top five all lapping sub-1:10, Fernando Alonso was sixth fastest for Ferrari, with Daniel Ricciardo and Sebastian Vettel both creeping into the lower reaches of the top ten at Red Bull's home race.
It was a difficult session for Jenson Button, meanwhile, whose McLaren returned to the pits early on billowing smoke.
A right-rear brake failure was diagnosed but Button was unable to play any further part and was therefore unable to try out the supersoft tyre ahead of qualifying.
That session starts at 1pm BST, although drivers will have to be more careful approaching Turn 8, where quite a few have got in the habit of running wide so far this weekend.
Attending the drivers' briefing on Friday evening, FIA Race Director Charlie Whiting confirmed that any driver crossing the white line of the corner exit with all four wheels of his car will be stripped of his lap time.
This weekend's Austrian GP is live only on Sky Sports F1. Race Day coverage begins with the Track Parade at 11.30am on Sunday