Portsmouth came from behind to defeat Bolton and increase the pressure on boss Sammy Lee, whose team have yet to pick up a point after three games.
Utaka scored after breaking from the half-way line
Nicolas Anelka shot through David James's legs to put Bolton in front but Kanu hooked the ball into the goal from six yards to equalise.
John Utaka then burst forward from 45 yards before slipping the ball home.
And Matthew Taylor scored a late penalty after Gerald Cid was penalised for a trip on Kanu.
It was a wet and windy afternoon on the south coast - and a miserable one for Lee, who has watched his team lose to Newcastle, Fulham and Portsmouth this season.
Lee's attempt to deploy a more attacking style than the system favoured by Sam Allardyce last season has yet to bear fruit and his team looked vulnerable defensively.
Bolton boss Lee prowled his technical area after the break, urging his team forward, but the second half was vastly inferior to the first, when both teams created a series of openings.
With just 12 minutes gone Anelka outlined exactly why he is the subject of recent transfer speculation, with Pompey one of the clubs said to be interested in signing the 28-year-old.
After collecting El-Hadji Diouf's pass down the left channel, the French forward accelerated towards goal and drilled the ball low and hard before the pursuing Hermann Hreidarsson could make a challenge.
Pompey, who had the better of the early exchanges prior to conceding, thought they had equalised two minutes later when Kanu headed home a corner, but the referee had already whistled for an infringement.
It seemed a harsh call, with both Kanu and Nicky Hunt appearing to compete equally.
Kanu, however, did restore parity after 16 minutes - with Bolton the team feeling aggrieved this time.
Hreidarsson seemed to tug Anelka's shirt on the half-way line but no foul was awarded and within seconds Pompey had scored.
The ball was slipped to Gary O'Neil down the right channel and his subsequent cross to the far post was superbly cushioned into Kanu's path by Utaka for the veteran Nigerian striker to equalise.
Both teams looked to push forward and Andranik Teymourian forced a decent save from James, while Benjani Mwaruwari headed over for Pompey.
Utaka's brilliant individual goal saw Pompey take the lead - the summer signing from Rennes collecting the ball just inside the Bolton half before sprinting towards goal and rounding Jaaskelainen before slotting home.
It was another frustrating afternoon for Bolton boss Lee
The chance had arisen after Bolton had needlessly surrendered possession and the lack of solidity from the visiting team must have been a concern for Lee.
In stark contrast with previous seasons, Bolton looked uncertain in defending corners and the home team enjoyed far too much space in the opposition area.
Benjani, for example, had plenty of time to position himself for a shot from eight yards that Jaaskelainen did well to save.
Pompey, who went into the game with a makeshift back four, seemed to have control of the match by the break, enjoying more of the possession and most of the attacking threat.
Lee introduced Christian Wilhelmsson for Andranik at the restart to try and skipper Kevin Nolan, who started the match up front and ended on the right side, was replaced by Daniel Braaten after 56 minutes.
Bolton created a decent opening when Gary Speed broke forward and forced a good save from James with a header.
But Pompey scored the game's decisive fourth goal close to full-time as the home team followed two draws with their first win of the season.
Portsmouth boss Harry Redknapp:
"This is one of the great wins for us. In the years I've been here that would be one of the very best of them.
"Today we had people playing in positions they've never really played before. It was a great performance.
"If we can do as well as last year we'll be happy because there are a lot of good teams in this league."
Bolton boss Sammy Lee:
"I'm not kidding myself. At times, when we played football in the right areas, I saw progress and I saw development.
"When we defend the way we did in certain instances and you don't keep a clean sheet, you'll struggle to win football games.
"We need to defend better. I don't just mean the back four, I mean the whole team. But we'll turn it around."
Portsmouth: James, Traore, Hreidarsson, Distin, Taylor, O'Neil (Cranie 82), Davis, Hughes, Utaka, Mwaruwari (Nugent 73), Kanu (Mvuemba 90).
Subs Not Used: Ashdown, Duffy.
Goals: Kanu 16, Utaka 30, Taylor 88 pen.
Bolton: Jaaskelainen, Hunt (Helguson 86), Cid, Meite, Samuel, Teymourian (Wilhelmsson 46), Alonso, Speed, Diouf, Nolan (Braaten 56), Anelka.
Subs Not Used: Al Habsi, Sinclair.
Booked: Hunt, Speed.
Goals: Anelka 12.
Ref: Steve Tanner (Somerset).