Southend were held to a third successive 0-0 draw at Roots Hall as Plymouth returned home to Devon with a point.The Shrimpers handed a debut to new loan signing Joe Pigott, who went straight in to the side after joining from Charlton, but Phil Brown's side were still unable to make the breakthrough.Pigott was immediately involved in the opening exchanges when he teed-up Ryan Leonard, who volleyed wide of the right-hand post from 10 yards out against his former team.But Plymouth soon hit back and should have opened the scoring when Lewis Alessandra charged through on goal only to see his low shot blocked by the legs of Blues goalkeeper Daniel Bentley.Shortly afterwards, Bentley also did well to deny Argyle's Andy Kellett, after the visiting left wing-back had twisted past Adam Thompson twice inside the penalty area.After the break, Shaq Coulthirst was twice denied by Plymouth keeper Luke McCormick before the visitors almost won it late on when Tom Flanagan flicked a close-range shot against the crossbar.