Blackburn grabbed a 1-0 win thanks to a second-half goal from Colin Kazim-Richards, with key players rested as the Gunners are knocked out of yet another competition
The likes of Jack Wilshere, Theo Walcott and Santi Cazorla were named on the bench ahead of the clash with Championship side Rovers, with all three coming on as the Gunners floundered.
But only a minute after the star names had been introduced, Colin Kazim-Richards found the back of the net from a rebound, after Wojciech Szczesny had pushed out Martin Olsson's shot into the area.
For all the dominance that Arsenal possessed, they found a barrier to goal in 22-year-old keeper Jake Kean, while Tomas Rosicky had a shot crash off the crossbar in the second half.
But in truth, the Gunners did not do enough to deserve anything from the match, with their first half display in particular bothersome for the home fans.
With the Gunners 21 points shy of Manchester United in the Premier league, the result means that if Arsenal fail to win the Champions League this year, they will have gone eight years since their last trophy win, the 2005 FA Cup.
Blackburn boss Michael Appleton insisted that their tactics were in place to simply allow the Gunners possession and force them out wide, but that his side take pride in their organisation and defending.
"We're quite happy with [allowing opposition to have more possession]," Appleton told reporters. "You don't win games of football without being organised... [and we] take pride in keeping clean sheets and enjoy defending.
"We try to show teams down the outside and defend crosses."