Smith and Haddin heap more misery on England
Australian batsman Steve Smith (R) plays a cut shot on the first day of their fifth Ashes Test match against England, at the Sydney Cricket Ground, on January 3, 2014
The Australians, sent into bat after Alastair Cook's first toss win of the series, stormed back from a parlous 97 for five to leave the beleaguered tourists in familiar trouble by opening day stumps.
Australia were all out for 326 late in the day with England losing the wicket of Michael Carberry for a duck to reach stumps at eight for one with Cook on seven and nightwatchman Jimmy Anderson one.
Smith and Haddin rescued the home team with a 128-run sixth-wicket stand before Haddin went for his sixth score over 50 in the series and Smith was last man out for 115.
Paceman Ben Stokes finished with six wickets for 99 as easily the best English bowler.
"I haven't played with too many nerves in this series. I've felt quite good every time I've gone to the crease," Smith said.
"Obviously I haven't converted into big scores as much as I would have liked, but I've certainly felt good at the crease and today, I guess, was my day."
Smith didn't dwell long in the 'nervous nineties' with a six and four off debutant leg-spinner Scott Borthwick to raise his third Test century against England and first at his home Sydney Cricket Ground.
Smith on 99 was gifted with a Borthwick full-toss and he clouted it through to the mid-wicket boundary.
The number five cracked 17 fours and a six in his 154-ball century. It was Australia's ninth century of the series, while England have just one.
Haddin, the bane of the English bowlers in this series, was finally out for 75 off 90 balls post-tea to help in the rescue act with Smith.
Haddin has had a golden series scoring 465 runs at 66.42 and has played a crucial role in rescuing Australia on numerous occasions in the one-sided Ashes.
Stokes spearheaded the under-manned English bowling attack, which was weakened when Boyd Rankin went off with a hamstring injury while bowling his ninth over.
Stokes claimed the wickets of Ryan Harris, Peter Siddle and Smith in his 20th over to wrap up the Australian resistance.
"We started really well. We had them 90-odd for five and then Haddin and Smith counter-attacked that start that we got," Stokes said.
"I think they got 50, 60 too many we would have liked. I’m pretty happy to get six wickets. The bowling is always improving."
Haddin came to the crease following the dismissal of George Bailey for another low score putting his Test place in great jeopardy ahead of the coming tour to South Africa.
Bailey was dismissed for just one, edging Stuart Broad for a Cook catch at first slip, who clung on at the second attempt.
England claimed four wickets before lunch after Cook won the toss.
Stokes dismissed opener Chris Rogers (11) and skipper Michael Clarke (10) and in the final over of the morning Anderson trapped Shane Watson leg before wicket for 43.
Rogers, who scored 116 in Australia's eight-wicket victory in the fourth Test, attempted to pull only to drag the ball on to his leg stump.
And Stokes claimed the big breakthrough when he coaxed an edge off Clarke to Ian Bell in the slips.
Australia lost the wicket of David Warner in the first hour, bowled by Broad for 16.
Young Durham leg-spinner Borthwick claimed his first wicket in his fifth over in Test cricket late in the day when he enticed Mitchell Johnson to hit lustily to substitute Joe Root at long-on for 12.
Borthwick was among three English changes from Melbourne, with Test debuts also for middle-order batsman Gary Ballance and Rankin.
Australia, who are chasing a 5-0 sweep for only the third time in Ashes history, remained unchanged for the fifth consecutive Test after all-rounder Watson (groin) and paceman Ryan Harris (knee) were cleared to play.
England sprung a surprise by dropping Root and elevating Ian Bell to number three.