"We've played without them this season plenty of times and got results. I don't know what it was today. We just didn't perform the way we know we can, the way we were performing before the international break."
United forced Bolton goalkeeper Jussi Jaaskelainen into just one save during the game, despite enjoying the lion's share of possession.
"We didn't create many chances and that's disappointing," Giggs said. "We got ourselves into good positions but were lacking some composure in the final third. In tight games like this you have to punish their mistakes on capitalise on your own good play - we didn't do that."