Swansea's hopes of challenging for second spot in the Championship were dealt a severe blow as their away-day blues continued at Portsmouth.
The dull goalless draw at mid-table Pompey halted a run of four straight defeats on their travels, but the promotion hopefuls hardly threatened.
Aaron Mokoena wasted Pompey's best chance, sending a free header wide.
Scott Sinclair sliced a volley from six yards as Swansea pressed late, before Stephen Dobbie's drive was well saved.
The result leaves Swansea in fifth place, six points adrift of second-placed Norwich City, with only three games remaining.
Portsmouth, meanwhile, are meandering towards the end of the season with nothing to play for having climbed away from any relegation trouble in 14th place.
The home side shaded a first half low on quality, with both sides guilty of poor passing and a general lack of composure.
The only real openings came in the opening 10 minutes when defender Mokoena should have done better with a header from six yards, before Kevin Nugent's rasping low drive from 30 yards went wide.
Swansea, who had been urged to play without fear by manager Brendan Rodgers before the game, managed just one effort on goal before the break when Sinclair dragged a long-range harmlessly effort wide.
Sinclair, Swansea's top scorer with 22 goals, flashed another drive wide shortly after the break, a shot which this time caused at least some degree of alarm to Jamie Ashdown in the Pompey goal.
Kanu had come on after 38 minutes to replace the injured Dave Kitson, and the 34-year-old Nigerian spurned a half chance early in the second half when his hesitancy allowed Angel Rangel to nick the ball away as he prepared to shoot.
The visitors struggled to impose their trademark slick passing style as the game wore on without incident, but Rodgers' side did finally begin to exert some pressure as they strived for the vital three points in the final 10 minutes.
Sinclair had the goal at his mercy but failed to connect cleanly with make a left-foot volley from six yards, allowing Ashdown to save comfortably.
Angel Rangel's screams for a penalty were ignored as the Catalan right-back went down under Carl Dickinson's challenge in the box.
And the late flourish ended with Ashdown blocking substitute Dobbie's fierce effort, with Nathan Dyer then inches away from poking the ball home after a desperate goalmouth scramble.