The Royals have now picked up just one point from a possible 15 on their Premier League travels and despite lying 12th in the table find themselves just three points clear of safety.
Rampant Rovers had the game wrapped up within barely half an hour as three goals in the space of 15 minutes from Benni McCarthy, Roque Santa Cruz and Tugay left the visitors stunned.
But rather than criticising into his players, Coppell instead insisted the buck stops with him following a result which gave him little reason to celebrate his 200th game in charge of the Royals.
Asked if confidence was shredded in the dressing room, he replied: "No. It's me, it's my fault. I chose the wrong way of playing, 100%. Their (the players') confidence is fine."
The Royals looked a different proposition in the second half following the introduction of Kevin Doyle, with the Republic of Ireland international twice on the scoresheet with headers, prompting Coppell to be asked why the striker had not been used from the start.
But the Reading boss defended the decision, citing Doyle's international involvement last week as the reason for him being named among the substitutes.
He said: "I will chop and change whenever I see fit but I obviously made the wrong call today.
"One of the reasons for the changes was because of the internationals who had played two games.
"Ivar (Ingimarsson), Brynjar (Gunnarsson) and Doylo had played two games. If you look at Doylo and his contribution he runs a million miles in those games.
"It's very hard to ask him with all the travelling involved to then give his best (today).
"If you play international games and you win it doesn't seem so physically demanding but if you get beat sometimes I think it takes more of a toll if you lose international matches.
"I know how proud the Irish and the Icelandic boys are so I wanted to cater for those three."
Their best was not to prove enough though as Rovers recorded their fifth straight victory in all competitions.
McCarthy celebrated his return to the side by opening the scoring in the 17th minute, showing considerable poise to guide the ball home from Santa Cruz's header across the face of goal.
Rovers may have played more games than any other top flight side this season but there was nothing sluggish about their play and within five minutes it was 2-0.
David Dunn slid in Santa Cruz and Rovers' leading scorer made no mistake, firing low into the left corner for his sixth goal in all competitions.
Then it was Tugay's turn, the Turk unleashing an unstoppable drive into the top-right corner to complete a first-half performance which even took Rovers boss Mark Hughes by surprise.
"To be three goals up at half-time is something of a rarity for me, I don't think I have had the experience of going in at half-time 3-0 up, but I quite enjoyed it," he said.
"I thought we were excellent in the first half. Some of our play was really inventive, certainly in the final third.
"Our interplay, our rotation of positions and the way we moved the ball quickly gave Reading a real problem at times and I thought they found it hard to cope at times."
A McCarthy penalty, sandwiched between two carbon copy Doyle headers, after substitute Matt Derbyshire was clumsily clipped, ensured Rovers claimed their first victory at home over the Royals for 27 years.
And although the Blackburn boss admitted his side were guilty of taking their foot off the pedal, he insisted it would have been hard for them to continue their first-half exploits for the full 90 minutes.
"In the second half maybe there was always a danger that the intensity to our play was just a little bit down on the first half which is understandable to a certain extent," added Hughes.
"But we were never in danger of losing the game. We're disappointed that we have conceded two goals but apart from that we were good value today."
PA Sport