Viduka has not found the net for six matches going back to 30 August at Middlesbrough.
He bagged 13 at the end of last season in his last nine appearances in a final total of 22.
Ahead of tonight's Carling Cup third-round clash with Manchester United at Elland Road, Reid told the Yorkshire Evening Post: "When the chance fell to him on Saturday (at Liverpool), I was right behind him and I thought 'goal', but at least he has hit the target.
"The only way forward for him is to keep working hard and keep playing because he's too good a striker.
"Fortunately for me he went on a run last year and scored goals. He is that type of striker and hopefully it will come again sooner rather than later.''