Marcus Harness made sure Portsmouth avoided an upset as they beat in-form non-league side Harrow Borough 1-0 to reach the second round of the FA Cup.

The former Burton striker tapped the ball into an open net to celebrate his sixth goal of the season as Sky Bet League One side Pompey were forced to scrap against the minnows.

Harness slotted in a Mahlon Romeo centre to open the scoring in the 28th minute, ending a four-game run of clean sheets for in Southern League Premier South outfit Boro, who had won 15 of their last 17 matches.

Moments later Romeo again found acres of space on the right flank but this time his identical low cross was met by air kicks.

Harrow, who are 83 places below Pompey, created chances of their own; livewire striker James Ewington almost capitalised on a weak back pass and fired a low strike at Gavin Bazunu.

Harness struck a post early after the break but Harrow asked questions throughout the second half, with Bazunu forced to make a flying stop to deny Boro’s George Moore.