Joe Ford's penalty was the only score in the first half as the home side went into the break with a 3-0 lead.
Ford and Elliott Davies then traded three-pointers after the interval before Easter's try took the hosts 13-3 clear.
Davies added another from the tee to take the Warriors to within seven points, but Ingall's touchdown secured the Sharks' second win of the tournament.
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One of Worcester's two victories this season came in this competition - a 21-16 success over the Cardiff Blues - and it gave them a chance of qualifying for the semi-finals, as they went into this encounter in second place in Pool Three.
Dean Ryan's men were also looking to build on last week's defeat of Oyonnax in the Amlin Challenge Cup at Sixways.
The director of rugby therefore chose to field some of his first choice players - but it was an inexperienced Sharks' outfit that started the brighter.
Just five minutes had elapsed when the Warriors infringed in front of their own posts and Ford duly converted a simple opportunity to take Sale 3-0 in front.
From thereon in the action mainly took place between the 22s as Worcester dominated the set- piece battle but found it difficult to penetrate the home side's rearguard with ball in hand.
The scrum, in particular, was proving to be a potent weapon for the visitors, even if they failed to truly capitalise on their dominance.
Debutant fly-half Elliott Davies had two chances to get the Midlands' outfit on the scoreboard but, kicking into the wind, his efforts drifted wide of the posts.
Sale's Phil Mackenzie then sprung into life late in the first period, evading the attention of a number of defenders before - in keeping with the quality of the game - the move broke down.
That ended what was an otherwise dire half of rugby and, despite Ford adding to his tally with a second three-pointer, the initial stages of the second did not prove to be much better.
On 50 minutes, Worcester finally managed to mount some concerted pressure on Sale and it ended in Davies reducing the arrears via a penalty.
But Steve Diamond's team found an element of continuity after that score and, following a succession of phases close to the line, Easter powered over.
Although the Warriors hit back with Davies' second from the tee, the hosts were in control and Andy Forsyth's scything break was finished off by Ingall to seal the win.
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