Jack King notched his first goal for the club to put United ahead but Ajay Leitch Smith’s low strike ensured a share of the spoils.
Mark Robins made three changes to the side that drew at Leyton Orient in the Emirates FA Cup last week, with Tommy Rowe and Neal Bishop returning to the midfield after being cup-tied and suspended respectively.
They replaced Sean McAllister and Hakeeb Adelakun in the starting line-up whilst Kevin van Veen was given the nod up front ahead of Darius Henderson.
After a cagey opening few minutes, it was the home team who threatened first as neat footwork from Sam Kelly saw him slot Leitch-Smith in on goal.
Iron ‘keeper Luke Daniels kept out the forward’s eventual effort with an instinctive save but the linesman did raise his flag to signal for offside.
Just seconds later, United had their first opportunity of the afternoon as Ryan McGivern slipped and allowed van Veen to motor down the right wing before lofting a delicate cross towards Paddy Madden but he directed his header inches wide.
Vale shot stopper Jak Alnwick was then almost bamboozled by a long Luke Williams free-kick, diving to his left to save at the final moment as the ball crept towards the bottom corner.
Leitch-Smith was proving to be a handful for the Iron defence as he whizzed a dangerous low centre across the face of goal before making space for himself in the area and hitting a drilled attempt narrowly over.
Wet weather on the morning of the match meant playing conditions were far from ideal and both teams were finding it difficult to string any lengthy passing moves together as the half hour mark approached.
This was emphasised when Anthony Grant galloped past a couple of challenges and made his way into the United box before falling under his own feet as he pulled the trigger.
The deadlock was broken in the 36th minute as Scott Laird won a corner on the left which Williams swung in towards King, who got in front of his marker and flicked the ball into the back of the net, via the upright.
One almost became two straight after as van Veen found Madden on the edge of the area and he dodged past McGivern before nonchalantly striking with the outside of his right boot, only to see his shot drop just the wrong side of the post.
Williams also went close when his powerful drive was palmed away by Alnwick but United were then pegged back as the hosts found an equaliser in first-half injury time.
The menacing Leitch-Smith latched onto a low through ball, managing to get it out of his feet before dispatching into the far corner to level things up in what was the final action of the opening period.
The second 45 minutes began as the rain began to pour down, which was only making it even more difficult for both sets of players to carve out opportunities.
Goal scorer King did however almost doubled his account when Madden collected the ball on the left before teeing up the midfield man but his first-time strike flew over.
Kyle Wootton was introduced in place of van Veen as the Iron shuffled their pack but it was Vale who were next to go close.
Grant was fouled on the edge of the area and former United player Michael O’Connor hit the resultant free-kick against the crossbar which then initiated a goalmouth scramble, though the danger was eventually cleared.
Substitute Wootton came within millimetres of putting the Iron ahead once more as a wicked low centre from Madden was hacked away from the youngster at the last by Richard Duffy, with the goal gaping.
The Valiants then went right up the other end and forced Daniels into a fine stop as Kelly’s cross-cum-shot had to be tipped away by United’s no.1, when the ball looked to be sneaking into the far corner.
As the clock ticked down, Jamie Ness replaced Williams but the drenched surface continued to thwart the flow of the contest.
Daniels was forced into two more saves as fullback Ben Purkiss was denied at the near post and McGivern saw a powerful strike pushed away, however 1-1 was how it stayed.
Port Vale: Alnwick, Purkiss, McGivern, Duffy, Birchall (Foley, 75), O'Connor, Dodds (Ikpeazu, 64), Yates, Kelly, Leitch-Smith (Hooper, 85), Grant.
Substitutes not used: Neal, Streete, Daniel, Dean-Conteh.
Scunthorpe United: Daniels, Wiseman, Goode, Canavan, Laird, Bishop, King, Rowe, Williams (Ness, 82), Madden, van Veen (Wootton, 65).
Substitutes not used: Anyon, Clarke, Boyce, Adelakun, Henderson.
Attendance: 3,983 (221 away).
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