Blackburn are second in the Championship, while West Ham are 15th in the Premier LeagueChampionship side Blackburn Rovers moved into the last 16 of the Carabao Cup as they beat West Ham 10-9 in an epic penalty shootout.
The match finished 2-2 after 90 minutes, and 19 penalties were scored before Angelo Ogbonna hit the crossbar.
Blackburn had taken the lead after only six minutes through Jack Vale's calm finish, before Pablo Fornals levelled.
Michail Antonio's low shot made it 2-1 but Ben Brereton Diaz's 88th-minute equaliser took the tie to penalties.
Blackburn won the League Cup in 2002 and are now on their best run in the competition since 2011-12, when they reached the quarter-finals.
The draw for the last 16 will take place on Thursday, following the final third-round tie between Manchester United and Aston Villa at Old Trafford.
With West Ham 15th in the Premier League and Blackburn second in the Championship, both managers opted to change their entire starting 11s from their previous matches.
The visitors took a sixth-minute lead as Tayo Edun's through ball was finished by Vale, but Fornals equalised in the 38th minute after Blackburn failed to deal with Antonio's cross.
West Ham, who have have never won this competition, looked to be heading through to the last 16 when Antonio's low strike found the back of the net with only 12 minutes to go.
But Chile international Brereton Diaz blasted in a late leveller before a high-quality penalty shootout.
With only the goalkeepers still to take a spot-kick, Ogbonna become the only player to miss, hitting the crossbar as the Hammers were eliminated and Blackburn advanced.
Line-ups
West Ham
Formation 3-4-3
13Aréola
2Johnson27Aguerd21Ogbonna
5Coufal32Coventry10Lanzini33Emerson
12Downes9Antonio8Fornals
13Aréola2Johnson27Aguerd21Ogbonna5CoufalSubstituted forBowenat 77'minutes32CoventrySubstituted forBenrahmaat 65'minutes10Lanzini33EmersonSubstituted forCresswellat 90+2'minutes12Downes9Antonio8FornalsSubstituted forScamaccaat 77'minutesSubstitutes
3Cresswell4Zouma7Scamacca15Dawson20Bowen22Benrahma28Soucek35Randolph47HegyiBlackburn
Formation 4-2-3-1
13Pears
11Rankin-Costello17Carter15Mola7Edun
21Buckley36Wharton
18Markanday23Dack10Dolan
29Vale
13Pears11Rankin-Costello17CarterBooked at 9mins15MolaSubstituted forHyamat 79'minutes7Edun21Buckley36WhartonSubstituted forGarrettat 45'minutes18MarkandaySubstituted forSzmodicsat 59'minutesBooked at 76mins23DackSubstituted forBreretonat 59'minutes10Dolan29ValeSubstituted forHirstat 85'minutesSubstitutes
1Kaminski5Hyam6Morton8Szmodics14Hirst22Brereton30Garrett33Phillips40BattyLive Text
Match ends, West Ham United 2(9), Blackburn Rovers 2(10).
Penalty Shootout ends, West Ham United 2(9), Blackburn Rovers 2(10).
Penalty missed! Still West Ham United 2(9), Blackburn Rovers 2(10). Angelo Ogbonna (West Ham United) hits the bar with a left footed shot.
Goal! West Ham United 2(9), Blackburn Rovers 2(10). Jake Garrett (Blackburn Rovers) converts the penalty with a left footed shot to the bottom right corner.
Goal! West Ham United 2(9), Blackburn Rovers 2(9). Nayef Aguerd (West Ham United) converts the penalty with a left footed shot to the bottom left corner.
Goal! West Ham United 2(8), Blackburn Rovers 2(9). George Hirst (Blackburn Rovers) converts the penalty with a right footed shot to the bottom left corner.
Goal! West Ham United 2(8), Blackburn Rovers 2(8). Flynn Downes (West Ham United) converts the penalty with a right footed shot to the bottom right corner.
Goal! West Ham United 2(7), Blackburn Rovers 2(8). Hayden Carter (Blackburn Rovers) converts the penalty with a right footed shot to the bottom left corner.
Goal! West Ham United 2(7), Blackburn Rovers 2(7). Aaron Cresswell (West Ham United) converts the penalty with a left footed shot to the bottom left corner.
Goal! West Ham United 2(6), Blackburn Rovers 2(7). Joe Rankin-Costello (Blackburn Rovers) converts the penalty with a right footed shot to the bottom right corner.
Goal! West Ham United 2(6), Blackburn Rovers 2(6). Ben Johnson (West Ham United) converts the penalty with a right footed shot to the top right corner.
Goal! West Ham United 2(5), Blackburn Rovers 2(6). Tayo Edun (Blackburn Rovers) converts the penalty with a left footed shot to the top right corner.
Goal! West Ham United 2(5), Blackburn Rovers 2(5). Manuel Lanzini (West Ham United) converts the penalty with a right footed shot to the centre of the goal.
Goal! West Ham United 2(4), Blackburn Rovers 2(5). Sammie Szmodics (Blackburn Rovers) converts the penalty with a right footed shot to the bottom left corner.
Goal! West Ham United 2(4), Blackburn Rovers 2(4). Michail Antonio (West Ham United) converts the penalty with a right footed shot to the bottom left corner.
Goal! West Ham United 2(3), Blackburn Rovers 2(4). John Buckley (Blackburn Rovers) converts the penalty with a right footed shot to the bottom left corner.
Goal! West Ham United 2(3), Blackburn Rovers 2(3). Gianluca Scamacca (West Ham United) converts the penalty with a right footed shot to the bottom left corner.
Goal! West Ham United 2(2), Blackburn Rovers 2(3). Tyrhys Dolan (Blackburn Rovers) converts the penalty with a right footed shot to the bottom right corner.
Goal! West Ham United 2(2), Blackburn Rovers 2(2). Jarrod Bowen (West Ham United) converts the penalty with a left footed shot to the bottom right corner.
Goal! West Ham United 2(1), Blackburn Rovers 2(2). Dominic Hyam (Blackburn Rovers) converts the penalty with a right footed shot to the top left corner.
