Sciver-Brunt only returned from a torn left calf last week, but after leading England's recovery with 48 runs to leave them needing nine for victory on Tuesday (Wednesday AEST), she trudged off the field in Southampton.
England reached a meagre 119 target with 15 balls to spare to move on to four points in Group B and put themselves in pole position to reach the semi-finals, but the main talking point will be if their captain will be available in four days against Scotland at Headingley.
"Just precautionary. Felt a bit of tightness in my calf and didn't want to push it," Sciver-Brunt said.
"We can't take any game lightly. We found that in the previous T20 World Cup when it came down to net run-rate. Hopefully we can keep winning.
"Really happy. Two different looking games, but we got over the line."
Ireland are now without a win in 19 matches at this event, but gave England a minor fright as Amy Jones (9), Danni Wyatt-Hodge (16) and Alice Capsey (5) were all dismissed within the space of 10 deliveries.
Jones skewed left-armer Aimee Maguire (2-23) high to Ireland captain Gaby Lewis at mid-on and Wyatt-Hodge, who made a match-winning century in England's 87-run win over Sri Lanka on Friday, followed in identical fashion two balls later.
Capsey was cleaned up by a superb slower-ball yorker from allrounder Orla Prendergast (2-17) as England lurched from 0-27 to 3-35, having made a record 1-219 last time out.
Ireland's 9-118 meant Sciver-Brunt and her predecessor as England captain Heather Knight (26) did not have to take too much risk and they rebuilt the innings with a 64-run partnership in 49 balls.
A collective disciplined bowling performance meant the home side were in the driving seat at halfway.
Amy Hunter (6) and Lewis (0) perished to premeditated sweeps and when Alana Dalzell (14) miscued to extra cover, Ireland were three down in the powerplay and relying on Prendergast to bail them out.
Prendergast (26) used the crease well, hammering Ecclestone for fours in an over costing 13, but the Irish star's cameo ended when she under-edged Gibson on to her stumps.
Ireland trickled along thereafter, only reaching three figures in a penultimate over where Ecclestone, who finished 3-22, claimed the wickets of lower-order duo Arlene Kelly (7) and Cara Murray (1) to catches inside the ring.
Little (26 not out) at least made sure Ireland's innings ended with a flourish with four boundaries in a wayward final over from Lauren Bell (1-39) – the only England bowler to go at more than a run a ball.
