The victory, Pools' fourth in a row, came despite having Jack Compton sent off in the 24th minute.
They were, however, indebted to goalkeeper Scott Flinders for a string of fine stops to keep them in the game.
Compton was dismissed for a studs up challenge on Jamie Reckford, and referee Scott Mathieson showed an instant red card.
Flinders made two fine low saves at his near post from Reuben Reid and Romauld Boco after a free kick found its way through to the six yard box.
The Pilgrims started the second half well, Flinders making two early saves, before Pools took the lead in the 55th minute.
Andy Monkhouse flicked on and James tore past Neale Trotman on the edge of the area and clipped a low, angled finish across keeper Luke McCormick.
Flinders saved instantly from Conor Hourihane and from then on, Pools defended superbly and in numbers.
The keeper kept out more efforts from Luke Young, Trotman and Reuben Reid as they saw the game out.