The Red Devils were title contenders in the Premier League until the final day of the season but were knocked out of Europe's premier club competition in December, after only securing victories against lowly-ranked Romanian side Otelul Galati.
“It’s fair to say we threw that one away,” Sir Alex told The Sun.
“That won’t happen again next season. We’ll qualify from the group stages. I’ll make sure of it.”
|KINGS OF EUROPE?
|12/1||Manchester United are 12/1 to win the 2012-13 Champions League with bet365|
The 70-year-old insisted his side will prepare to compete on all fronts this time, and continued: “European football is hugely important to us and we must compete for the biggest trophies.
“We need to make a statement — and show everybody last season was just a blip.”