Celtic must spend before they consider challenging for European honours, Manchester United captain Roy Keane has said.
Celtic reached the UEFA Cup final last season before falling to Porto in Seville. But, after yesterday's 4-0 defeat by United in Seattle, Keane believes his boyhood heroes must spend big money to become a genuine threat.
He said: "Celtic are an excellent team and have an excellent manager but like everyone else you have to keep looking to improve. Celtic just came up short in the league and in the UEFA Cup, like we did against Real Madrid, and there is such a fine line between winning and losing at the top level.
"The Champions League is hard. That's where you need the top players and going by the UEFA Cup Final last season, Celtic lack that bit of magic . . . and when you consider their transfer fees and wages, it's going to be difficult for the likes of Celtic".
Manchester United and Celtic are touring the United States ahead of their respective league campaigns, which get under way next month.