Alex Ferguson failed in a deadline-day move to resurrect a deal to sign Marcos Senna from Villarreal.
Senna had been placed towards the top of Ferguson's shopping-list as the Manchester United boss looked to strengthen his midfield in the summer.
But with his attempt to land Owen Hargreaves from Bayern Munich getting tantalisingly close, Ferguson told Senna and his club he could not push through a proposed transfer for the 30-year-old.
The decision backfired as the August 31st deadline drew closer with Hargreaves forced to see out his Bayern contract until 2010.
So, Ferguson was forced to go back to Villarreal with an improved offer for Senna, which was promptly rejected, leaving United with only one major signing, £18.6million England man Michael Carrick.
Ferguson told United Review: "We did work very hard on trying to bring Owen Hargreaves to Old Trafford, right up to the day the transfer window closed.
"Similarly, we made another late bid for Marcos Senna at Villarreal, but you cannot force clubs to sell and so we open our campaign with what we have got."
Ferguson recognises many fans are concerned at the lack of transfer activity.
Yet, after four straight Premiership wins, he feels his squad is strong enough to cope with the twin demands of fighting for success at home and abroad.
He added: "Some of you may not share my confidence, especially if you were expecting more from the transfer market this summer.
"But I am not dissatisfied with my squad. You always seek to add to your options but we have a good squad well equipped to make a serious challenge on all fronts.
"You can see that from our recent league performances and I believe it will take something strange to stop us qualifying from our Champions League group this time." PA