Plymouth remain in the League Two play-off places despite being held to a 0-0 draw by Oxford United at the Kassam Stadium.In front of their biggest gate of the season, the U's extended their unbeaten run to five games, their best run of the campaign. Argyle could count themselves unlucky as Reuben Reid's powerful header come back off the underside of the bar in first-half stoppage time, the ball bouncing down on the goalline but crucially not crossing it. On a bobbly pitch, there were few clear-cut chances. Oxford striker Patrick Hoban, still looking for his first goal after 10 games for his new club, was guilty of two glaring misses in the first half. Hoban sliced wide from close range in the fifth minute after Callum O'Dowda sent over a dangerous low cross from the left, and later snatched at a very inviting volley eight yards out, blazing it high over the bar. In the dying seconds, Oxford's Kemar Roofe beat two players and fired in a powerful 20-yard drive - but it was straight at keeper Luke McCormick.