Returning Oli McBurnie helped Hull get back to winning ways as Phil Parkinson watched Wrexham's nine-match unbeaten league run come to an end from the stands following a 2-0 loss.
Just a point separated the Championship play-off hopefuls ahead of Wednesday's meeting at the MKM Stadium, where the Red Dragons boss served a one-match touchline ban.
Parkinson cut a frustrated figure as Wrexham deservedly went behind to a Kyle Joseph effort, with substitute McBurnie - making his first appearance since sustaining a calf injury in October - wrapping up the win for Hull after Ivor Pandur saved a Kieffer Moore spot-kick.
It was an impressive response by Sergej Jakirovic's Tigers to Friday's humiliating 4-1 home loss to Middlesbrough and propelled them up to sixth spot.
Hull began sharply even without top scorer Joe Gelhardt and opened the scoring after fine work down the right by Mohamed Belloumi, starting for the first time since September.
The 23-year-old attacked confidently and smartly cut back for Matt Crooks to get away a deflected shot that Arthur Okonkwo could only spill into the path of Joseph to squirm an effort home.
City so nearly undid that work with some comedy defending six minutes later.
Skipper Lewie Coyle's senselessly cleared a cross inside, with the ball hitting team-mate Crooks and falling kindly for Moore to strike narrowly wide.
It was the only shot Wrexham mustered in a one-sided opening period, with Joel Ndala threatening and Darko Gyabi wasting an opportunity before Okonkwo stopped a low Regan Slater strike.
Wrexham returned from the break with renewed intensity as Nathan Broadhead dragged wide from distance and then saw a 25-yard drive deflect over.
The summer signing earned a chance from the spot soon after as Crooks caught him with a clumsy challenge.
Moore stepped up to the 56th minute penalty and Pandur saved low to his right, where he seemed to have been indicating the striker would shoot.
Hull were enraged to have appeals for a pair of penalties for handball ignored shortly after, with skipper James McClean surviving one shout before Dom Hyam somehow got away with another.
Wrexham may have escaped there but they could not stop the hosts triumphing, with McBurnie settling things.
The 63rd minute introduction only needed four minutes to find the net as the Scotland international stretched to get a toe on Ryan Giles' low ball into the box.
Fellow introduction Liam Millar struck the crossbar and Okonkwo did brilliantly to prevent late substitute David Akintola grabbing Hull a third.
Hull's Sergej Jakirovic:
"That type of game [the defeat to Boro] happens sometimes.
"When you watch the game again, you couldn't believe it what they're doing there.
"We gave a lot, a lot, and this is also Boro's quality to punish your mistakes.
"But also we showed good reaction and this is in football always very, very important. They couldn't wait for a new game to show that it was a bad day at the office."
Wrexham's Phil Parkinson:
"We just weren't at the levels tonight and I've got to look at that - my part in it, all the staff will, and the players themselves.
"But we'll do that together. The lads have given us a lot but tonight we were below the level, and we'll come out ready for action at the weekend.
"It's very rare in my whole time at Wrexham to have a 45 minutes that was so unlike us.
"Tonight the first 45 minutes was certainly one of those performances, but against a good side as well. Give them credit, they were excellent.
"We will look to respond, of course. That's what football's all about.
"We'll be a bit flat tomorrow because we don't like losing. Nobody does in football, but we'll work together as a group, and we'll look to putting up a good performance on the weekend."
