A stalemate here will be enough for the hosts to retain the Ashes after victories at Trent Bridge and Lord's. But England must work hard to do so, and the follow-on target of 328 is sure to loom large throughout today.
Captain Alastair Cook (53 not out) has taken it upon himself to lead from the front in an awkward situation, but lost the assistance of Jonathan Trott on the way from 52 for two to 79 for three on a sunny morning.
Only 10 runs came in the first half-hour, including a Cook four off his legs past straight midwicket off Ryan Harris.
The accuracy of Harris and Peter Siddle then paid off when the former got one to bounce sufficiently off a length, and hold its line, for Trott to fence a catch low to second slip.
New batsman Kevin Pietersen made a nervy start, including a fretful push at a wide delivery from Harris first ball - which he missed on its way through to the wicketkeeper.
Cook reached his near three-hour half-century by pushing Harris for two past mid off, though, having begun his patient vigil soon after tea yesterday.