At the interval Blackburn led, deservedly, by one of Andy Todd's rare scoring forays. Afterwards they were eclipsed and eventually humiliated, finishing with 10 men on the field when Paul Dickov drew a straight red card for a two-footed tackle on Paul Konchesky less than 10 minutes after coming off the bench. In a side containing four new signings and which needed a last-minute change at the back when Tomas Repka reported ill just before the kick-off, it was that smoothest of old hands, Teddy Sheringham, who stood out, marginally ahead of the superb Israel international midfielder, Yossi Benayoun.
The 39-year-old former England man slotted the equaliser within a minute of the second half, started the move for Nigel Reo-Coker's thunderous strike which put West Ham in front and had been withdrawn to rest those tiring limbs by the time Benayoun laid on a third for Matthew Etherington.
West Ham's manager, Alan Pardew, acknowledged that Sheringham was not best pleased at being withdrawn after 71 minutes. "I didn't like taking him off," said Pardew. "He is a superstar in my eyes. His personality is so important to us. But I wanted to kill the game and seal the victory." Instead, it was Blackburn who self-destructed with that Dickov dismissal.
Pardew called it "a great day for West Ham." So it was. To win their opening game in such emphatic fashion will do wonders for their self-belief, which was growing visibly in any case as they set the second-half tempo, a fast-paced one in which Benayoun's passing skills were complemented by the surging runs from midfield of Reo-Coker and the accurate crossing of Etherington.
Blackburn's deployment of the burly Shefki Kuqi alongside the quicksilver Craig Bellamy, rather than last season's top scorer Dickov, looked promising while West Ham were working their way into the match but if Kuqi's replacement by a midfielder, Vratislav Gresko - "to combat Sheringham, who caused us problems all day long" according to the Blackburn manager, Mark Hughes - further reduced Bellamy's chances to inflict damage, it did nothing to stem West Ham's flood tide.
Even before Todd's 18th-minute goal, Blackburn could have scored. A Robbie Savage free-kick was deflected and heading for the top corner of Roy Carroll's net until Konchesky managed to head it away for a corner. It was a corner soon afterwards, delivered low to the near post, which undermined West Ham. A half-clearance sent the ball in the direction of Todd, who walloped it back for his first goal since Boxing Day 2004.
A booking for Savage and a piece of Konchesky retribution which sent the Welshman into the advertising hoardings and drew a lecture indicated the game might be getting out of hand, but positive play was the winner until Dickov's moment of lunacy.
West Ham did not land a shot on target until 35 minutes had passed - from Sheringham, of course. He might have scored soon afterwards, seeing Brad Friedel recover well after spilling a cross to block Sheringham's stab.
A Pardew pep talk changed his team's outlook and inside a minute of the resumption, Benayoun sent a short pass into Sheringham's stride for him to cut back inside Todd and stroke home the equaliser. He was inches away from connecting fully with an Etherington centre as West Ham took control, but initiated the move for the second goal, sending a perfect ball out to Etherington.
As Sheringham moved into position for the cross, it was deflected by Aaron Mokoena and rolled out for Reo-Coker to strike spectacularly past Friedel.
There was a touch of suicide about Blackburn's involvement in the third West Ham goal. Brett Emerton sent the ball back towards his own goal from near the corner flag; it was seized by Benayoun, who drew the defence and slid a pass across the gaping goal for Etherington.
Any remote Blackburn hopes of rescuing something disappeared completely as Dickov floored Konchesky. Hughes, properly, had no sympathy. "If you raise both feet off the ground and catch your opponent you get red-carded," said the manager. "It was the wrong challenge to make." Poor Hughes must have wondered what on earth had struck his side. "I don't think anybody saw it coming," he said. "We have had a good pre-season and were expecting a continuation of that."