The pair had played just nine T20 internationals between them before taking the field at Cardiff – Willey accounting for just one of those – but did not waver when Morgan handed them death bowling duties at the SSE Swalec.
With two overs remaining Australia needed 20 for the win, with Steve Smith in formidable form on 89 not out.
Three balls later Willey had the touring captain caught in the deep and when asked to defend 12 from the last six balls, Stokes sealed victory in style.
He conceded only six, took the wicket of Nathan Coulter-Nile and effected two run-outs, keeping the coolest head in Cardiff.
“I hadn’t earmarked Ben, before the day had started, for bowling the last over of the game,” Morgan said.
“But the situation came where we had to bring our frontline bowlers back on to try and take the game that much further, to the 20th over.
“It was a tough one but he took on the responsibility of bowling that over really well.
“Playing with 12 (runs), the challenge was to get ahead on the over. That gives him a licence and a confidence to play the way he did.”
Morgan (74) and Moeen Ali (72no) had provided the platform for victory, sharing a wonderful stand of 135 in just 75 balls as England posted 182 for five.
But while he will look back with considerable satisfaction on his first competitive innings in a month, following an unscheduled break from Middlesex duty, he was equally keen to stress Willey’s role.
The Yorkshire-bound all-rounder also played a late starring role in the T20 win over New Zealand in June and is fast developing a reputation as a man for the big moment.
“He’s brilliant,” said Morgan. “A bit like Stokesy he just loves responsibility, he likes the limelight, he doesn’t shy away from taking it on. His attitude towards things, amongst others in the changing room, will go a big way to changing the culture the way we’ve tried to over the last few months.”
With Essex left-armer Reece Topley also showing signs of promise on his international debut, Morgan will head into the five-match one-day series in good cheer.
“We’ve an exciting group of young cricketers, even outside the 14 we selected for the ODI series. We probably have another four or five guys outside that pushing for places and earmarked for the future.
“It’s a very exciting time for us.”