Manchester United boss Sir Alex Ferguson challenged goalkeeper Tim Howard to prove his worth for the last time during the next string of games after Roy Carroll's blunder that cost United a result against AC Milan last week.

Howard started in place of Carroll for the league win over Portsmouth yesterday with forgotten Spaniard Ricardo on the bench, amid speculation Sir Alex Ferguson has given up hope in all three of his senior shot-stoppers.

American international Howard started his first Premiership game since September in the 2-1 Pompey win and had only played in the FA Cup and Carling Cup since his axe.

Ferguson admitted: "Roy Carroll made a big mistake on Wednesday,"

"I don't think he was totally responsible but maybe he is better out of it so I can give Tim Howard his go."

"We have the important game in Milan looming in 10 days' time and I want to see how Tim responds to the challenge." 

The likes of Sebastian Frey and Carlos Kameni have been linked to fill the goalkeeping void in recent days, topped off with speculation that Roy Carroll is refusing to commit his future at Old Trafford.