Scunthorpe suffered a 1-0 home defeat at the Sands Venue Stadium, with Port Vale’s Ben Garrity scoring the only goal of the game minutes before half-time.
United named an unchanged side from the one that drew 2-2 at Carlisle United a week earlier.
Six minutes into the match, Rory Watson was brought into action making an outstanding save after David Worrall found space on the right and having his low driven shot tipped out for a corner.
Minutes later, Myles Hippolyte had the Iron’s first effort on goal when he fired a left-footed strike towards goal which narrowly went wide of the post.
Thirteen minutes in, the Iron shot-stopper was forced into making another save when James Wilson cut inside from the right and hit the ball low at Scunthorpe’s No. 1.
Harry Wood had his own chance which was struck on the half-volley, but he couldn’t keep the ball down as it went straight over the bar.
Watson again kept the away side at bay after tipping captain Tom Conlon’s free-kick out for a corner.
Two minutes before half-time, Iron skipper George Taft connected with Wood’s free-kick, aiming his headed effort towards the bottom right which was saved by Lucas Covolan.
A minute later though, the away side took the lead through Garrity after he managed to find space down the left side of the area and snook his effort in at the near post from close range.
The Iron started the second half well, as four minutes in they immediately tested Covolan, with Alfie Beestin fizzing the ball towards goal, which was palmed away. Then, moments later, Beestin again struck a low shot from distance which the away goalkeeper gathered.
Fifteen minutes into the second half, Onariase met O’Malley’s looping cross and headed it towards goal but his shot was saved by the away keeper.
Scunthorpe made a double substitution on 63 minutes, taking off Hippolyte and Wood and they were replaced by Devarn Green and Hayden Hackney.
Former Iron loanee Jamie Proctor had a great effort for the away side when the ball broke for him 10 yards from goal, however he fired his shot wide of the left post.
Scunthorpe made their final change 15 minutes from time with Jordan Hallam being brought on for Jarvis.
Ross Millen’s drilled shot was deflected wide for a home corner as they pushed for an equaliser twelve minutes before the end.
Scunthorpe then almost levelled the score when Onariase had his right-footed shot cleared off the line by away captain Conlon.
United kept plugging away but couldn't find that equaliser and return to action with a trip to Newport County next week.
IRON: Watson, Millen, O’Malley, Taft, Onariase, Beestin, Hippolyte (Green, 63), Wood (Hackney, 63), Scrimshaw, Jarvis (Hallam, 75), Perry.
IRON SUBS NOT USED: Collins, Rowe, O’Neill, Pugh.
PORT VALE: Covolan, Gibbons (Benning, 69), Jones, Smith, Worrall, Garrity (Taylor, 77), Wilson (Lloyd, 74), Conlon, Proctor, Pett, Cass.
PORT VALE SUBS NOT USED: Stone, Johnson, Politic, Amoo.