David Dunn could hardly have picked a better time to score one of the goals of the season as he played his part in one of the best overall midfield displays the Premiership has seen so far this year.
Watched by Sven Goran Eriksson and playing in England's problem position on the left, Dunn contributed a sublime 30-yard chip for Rovers' second as West Ham were overrun.
That was the middle goal of three in 10 minutes of the first half which effectively won the game, although Blackburn went on to score four more after Tomas Repka was sent off for the second time in his short Hammers' career.
Although right-footed, Dunn did a fine job on the opposite flank. "He's as exciting as any midfield player around in the final third of the pitch," said his manager, Graeme Souness. "He's Gascoigne-ish and he'll be really pleased I've said that because I think he is his hero. Outside that, he's still learning the game, but going forward he puts you on the edge of your seat."
If there was a better player on the field it was Rovers' captain Garry Flitcroft, who played a commanding role in midfield. It was significant that it was he who got Blackburn moving, winning the ball on the edge of the area for Corrado Grabbi and then timing his run to head home after the Italian twisted, turned and eventually got his cross in.
Then came Dunn's little masterpiece. Receiving a diagonal ball from Henning Berg, he had the vision to see that there was just room to leave Shaka Hislop stranded and his execution was perfect.
Considering that two first-choice wide men, Keith Gillespie and Damien Duff, were missing, Blackburn did tremendous damage down the wings, with Damien Johnson starting and finishing the move for their third, a minute later. Tugay Kerimoglu, another who shone in midfield, crossed to beyond the far post and, when Grabbi headed back into the middle, Johnson was there to volley into the roof of the net.
Souness felt that the game could have turned out very differently if West Ham had taken either of their chances after half-time, Trevor Sinclair's header bouncing up over the bar and Frédéric Kanouté's going straight at Brad Friedel.
The dismissal of Repka, when he saw a second yellow card for clattering into Grabbi, also confirmed that this was going to be the day when Blackburn gave someone the beating their manager has been promising.
Almost immediately, Tugay fired in a shot from the left that was missing the far post and Grant McCann, one of two substitutes brought on at half-time to tighten West Ham's defence, lashed at it and deflected it in.
In the last 12 minutes, the visitors fell apart completely, the sort of collapse that leaves manager Glenn Roeder wondering how he is going to get them away from the foot of the table.
The Blackburn substitutes, Mark Hughes and Craig Hignett, gave Tugay the chance for a shot from outside the area almost as good as Dunn's had been. Dunn then cut in from the left to have his shot blocked and dispatched on the rebound by Matt Jansen for his second Premiership goal of the season.
In injury time, Dunn sent Jansen away and, although his shot went across goal, Hignett was there to tuck it away.
"If we carry on defending like that, we're going to be in serious trouble this season," said Roeder. "We're four or five players short of the squad we need," he said.
Goals: Flitcroft (18) 1-0; Dunn (27) 2-0; Johnson (28) 3-0; Carrick (39) 3-1; McCann og (63) 4-1; Tugay (80) 5-1; Jansen (82) 6-1; Hignett (90) 7-1.
Blackburn Rovers (4-4-2): Friedel 5; Neill 6, Berg 6 (Short 5, 71), Johansson 5, Bjornebye 5; Johnson 7 (Hignett 6, 75), Tugay 7, Flitcroft 8, Dunn 8; Grabbi 7 (Hughes 6, 75), Jensen 6. Substitutes not used: Mahon, Kelly (gk).
West Ham United (4-4-2): Hislop 5; Schemmel 4, Repka 4, Dailly 4 (Foxe 5, h-t), Soma 4; Sinclair 5, Carrick 6, Hutchison 4, Moncur 4 (McCann 5, h-t); Kanouté 6, Di Canio 5. Substitutes not used: Kitson, Defoe, Bywater (gk).
Referee: A D'Urso (Billericay) 4.
Bookings: Blackburn: Grabbi. West Ham: Moncur, Repka, Kanouté, Di Canio. Sending off: West Ham: Repka.
Man of the match: Flitcroft.
Attendance: 22,712.Reuse content