Shaun Wright-Phillips put his Spanish racism taunts behind him to ensure Portsmouth manager Harry Redknapp's own week of misery continued.
Wright-Phillips was subjected to vile taunts about his skin colour during England's friendly defeat in Spain on Wednesday.
But the midfielder was a key figure as City notched their second away win of the season.
Redknapp was close to walking out on Portsmouth following the appointment of Croatian Velimir Zajec as Pompey's new executive director on Monday.
The Pompey boss must have wished he had followed up that threat when Wright-Phillips opened the scoring as early as the fifth minute.
Serbian defender Dejan Stefanovic slipped inside his own penalty area gifting possession to Wright-Phillips.
The pint-sized winger had no hesitation in smashing the ball past Pompey's stand-in goalkeeper Jamie Ashdown from six yards.
The home side dusted themselves down to hit back three minutes later when Gary O'Neil bagged his first Premiership goal for more than a year.
O'Neil had been out in the cold before being recalled from a loan spell at Championship side Cardiff City following an injury crisis at Fratton Park.
O'Neil gave Redknapp a timely reminder of his ability by volleying the South Coast side level.
Defender David Unsworth ran free on the left before crossing for O'Neil to slot past David James at the back post.
Both sides were forced to make substitutions because of injury midway through the first half.
Lomana LuaLua, who came into the match struggling with groin and hip injuries, limped off to be replaced by City old-boy Eyal Berkovic in the 25th minute.
City boss Kevin Keegan was forced to withdraw Nicolas Anelka a minute later after the Frenchman had been clattered in a tackle by Pompey captain Arjan De Zeeuw.
Robbie Fowler came on in Anelka's place before Pompey midfielder Amdy Faye headed over from a Berkovic free-kick soon after.
O'Neil was denied a second goal when City defender Sylvain Distin charged down his long-range shot in the 29th minute as the teams went in level at half-time.
Wright-Phillips was almost celebrating a spectacular goal five minutes after the restart.
Richard Dunne picked him out with a sublime 40-yard pass and the youngster beat two Pompey defenders before firing just wide from the edge of the area.
Ashdown, in for the injured Shaka Hislop, produced a fine save to prevent Paul Bosvelt putting City back in front three minutes later. Bosvelt picked up the ball on the edge of the area before unleashing a curling shot which Ashdown pushed past the right-hand post one-handed.
Ashdown was on hand to deny Fowler a few minutes later, pushing the Liverpudlian's volley over the crossbar.
But the young goalkeeper could do nothing to prevent Antoine Sibierski making it 2-1 11 minutes from time.
Fowler got in behind the Pompey defence before picking out Sibierski with a pinpoint right-wing cross and the Frenchman planted a right-foot volley past Ashdown from near the penalty spot.
Redknapp's misery was compounded when Bosvelt sealed the win with City's third goal four minutes from the end.
Wright-Phillips split the Pompey defence in half and Bosvelt was on hand to turn the ball past Ashdown after the midfielder's shot had been saved.
MAN OF THE MATCH: Shaun Wright-Phillips (Man City) - Put the midweek incidents in Spain behind him in the best possible way, scoring one goal and making another.