The Hammers' bargain £10,000 capture from Wolverhampton Wanderers struck on 15 minutes, but after that unlucky Manchester City did more than enough to avoid the sixth successive defeat that leaves them in 13th place.
West Ham had made three changes following their excruciating 1-4 defeat at ten-man Chelsea, as Newton, James Walker and Bobby Zamora replaced the injured Matthew Etherington and the rested Shaka Hislop and Marlon Harewood.
After also losing in the capital at Spurs last weekend, City made just one switch with Albert Riera replacing Danny Mills as they desperately tried to halt their run of five straight losses, including an FA Cup sixth round defeat at the hands of the Hammers.
With City looking short on confidence and West Ham with an eye on next Sunday's FA Cup semi-final against Middlesbrough, both sides started sluggishly.
Indeed, the only thing to amuse the crowd in the opening exchanges was the sight of the shy Yossi Benayoun changing his shorts while shielded by the fourth official and the Hammers' physio.
But the absent City defence had more to be embarrassed about on the quarter-hour mark, when Zamora cleverly juggled Dean Ashton's flick-on before inviting Newton, galloping unmarked upfield, to open his account by drilling a clinical 18-yarder beyond exposed ex-Hammer, David James.
While the Hammers were well on top, City were destined to take control and, as the half-hour mark approached, both Hayden Mullins and man-of-the-match James Collins blocked goalbound efforts, before Richard Dunne ended the frantic scramble by blasting high over.
And then former East End wide boy Trevor Sinclair mis-hit a looping 20-yarder over Walker, only for his effort to be wiped out by an offside flag against Micah Richards.
Having replaced Ben Thatcher with David Sommeil at the interval, Pearce almost saw his side draw level on 51 minutes when the home defence parted in the wake of Sinclair's barnstorming run, only for Walker to brilliantly divert the former England international's low 15-yarder aside for a corner.
Add Lionel Scaloni's brilliant block on Georgios Samaras eight yards out, and City were threatening to equalise against a West Ham side that had seriously lost its way in a match poorly punctuated by the all too familiar blow of referee Steve Bennett's whistle.
Midway through the half, both number tens were introduced as Harewood and Antoine Sibierski replaced Zamora and Samaras and, on 75 minutes, Darius Vassell finally looked to have levelled when he diverted Riera's cross past Walker.
But, again, an offside flag wiped the smiles off the City faces and when the luckless Vassell lobbed the ball over the advancing Hammers' keeper shortly afterwards, he knew it was not going to be his day as Paul Konchesky hooked the ball off the line to secure three fortuitous points for Pardew's men.