Batsman James Taylor anchored the innings with his maiden one-day international century while opener Jason Roy struck 63 and Morgan 62 as England amassed 300-8.
The recalled Aaron Finch impressed with a half-century although Australia could only muster 207 all out as England spin duo Moeen Ali and Adil Rashid shared five wickets for the concession of just 73 runs.
Australia’s failure to hunt down what would have been the highest successful ODI run-chase at Old Trafford means England remain in contenion for a series win. They trail 2-1 with two matches remaining. The next clash is at Headingley on Friday.
“I was very impressed. We improved in the areas I asked the guys to from the first two games,” said Morgan.
“We set the standard with the bat at the top of the order and the two openers gave us a very good platform. Then me and James Taylor managed to get a really good partnership going in the middle.
“The games we’ve played so far the top score was 85 and we want guys to make match-winning contributions and James Taylor did that.
“We tried to put the bowlers under as much pressure as we could. We hadn’t done that in the first two games, but when an opportunity arose we managed to do it.”
Taylor has endured a stop-start ODI career but the decision to rest Yorkshire’s Joe Root for this series opened the door and he has seized his opportunity. His score of 101 last night built on knocks of 49 and 43 in the previous matches.
His partnership of 119 with Morgan formed the bedrock of the innings after openers Roy and Hales had shared an opening stand of 52. Roy was the dominant force and smashed a 45-ball 63 before falling to debutant Ashton Agar.
England’s innings stalled as Agar and fellow slow bowler Glenn Maxwell, together with seamer Pat Cummins, applied the brakes, although ultimately the hosts’ spinners out-performed their direct opponents. Rashid bowled his 10 overs unchanged, claiming 2-41 and snaring the crucial wickets of Finch and captain Steve Smith, the latter courtesy of a stunning catch by Steve Finn at short mid-wicket.
But Finn did not hold the monopoly on imperious catches. Roy plucked the ball out of the night sky at deep log on, at the second attempt while falling backwards, to dismiss Agar -- the second of three victims for seamer Liam Plunkett.
Moeen was the pick of the bowlers with 3-32, while Finn also picked up two scalps, including the final wicket of wicketkeeper-batsman Matthew Wade for an enterprising 42.
“I thought our two spinners were outstanding. It was set up by the start, we knew the first 15-20 overs with the new ball was going to set the tone so I think Steve Finn’s spell up top was really impressive,” added Morgan. “Then for the two spinners to come on and bowl with control – they didn’t really bowl that many bad balls in their 10 overs – I was very impressed, but not surprised.”