Shayne Lavery’s cute finish after 42 minutes looked to have sealed three points for the visitors.
An away victory then seemed assured after 80 minutes when Hull captain Lewie Coyle was sent off for a second bookable offence. But Eaves, a second-half substitute for Andy Cannon, salvaged a point for the struggling hosts when he smashed home Keane Lewis-Potter’s precise cross from the left after 84 minutes.
Hull won Sky Bet League One at a canter last season but they have found life back in the Championship an ordeal and have not won since the opening day of the campaign.
Torrential downpours admittedly blighted the flow of the game for much of the evening but the visitors adjusted better – especially during a drab first half.
But with the game going nowhere, Hull were suddenly energised when goalkeeper Chris Maxwell carelessly gifted possession inside his area.
Forward Mallik Wilks dithered and should have at least seized upon that error. That attacking naivety proved costly when a controlled Blackpool side gained the upper hand through Lavery.
Neat central interplay on the edge of Hull’s penalty area created room for Ryan Wintle to pass to Demetri Mitchell on the left flank. Mitchell’s cross was perfect, yet Lavery still did well to half-volley into the roof of the net.
Once Coyle was shown a second yellow card for a poor foul after 80 minutes, Hull could well have folded. But with the game seemingly up, Eaves somehow found space inside the Blackpool penalty area to convert Lewis-Potter’s sweet cross with his left foot.
In a frenetic finale, Hull substitute Tyler Smith might even have given his side a surprise victory but his strike from distance was well stopped by visiting goalkeeper Maxwell.
Hull City: Ingram, Coyle, Jones, Greaves, Elder, Docherty, Cannon (Eaves 77), Longman (Tyler Smith 58), Moncur (Bernard 85), Lewis-Potter, Wilks. Unused substitutes: Smallwood, Emmanuel, Baxter, Matthew Smith.
Blackpool: Maxwell, Sterling, Ekpiteta, Keogh, Garbutt, Mitchell (Bowler 62), Wintle, Dougall, Anderson, Madine (Yates 71), Lavery (John-Jules 85). Unused substitutes: Connolly, Husband, Stewart, Moore.
Referee: M Donohue (Lancashire).