The 31-year-old Socceroo scored twice to take his tally for the season to 19 as Boro stormed to a 3-1 victory which handed them a 12th-place finish in the Premiership.

Viduka was given a standing ovation when he was substituted in the final minute of normal time, and the home supporters among a crowd of 29,556 implored him to sign the contract extension he has been offered as the players returned for a lap of honour.

The former Leeds frontman gave nothing away in a radio interview conducted on the pitch, and Southgate is hoping for a positive answer within the next 10 days.

Southgate said: "He is going to think about things over the next few days. I suspect we will know in the next 10 days or so.

"He heads back to Australia to link up with their team, but I do not mind how long it takes if it is the right answer from our point of view."

Viduka demonstrated his ability with two excellent finishes, in contrast to the rest of his team-mates.

His 34th-minute strike put Boro ahead, and after young defender David Wheater had atoned for his own error in allowing Simon Davies to level by heading home Boro's second in first-half stoppage time, he added his second within a minute of the restart to clinch the points.

Southgate admitted his need to assess the squad when he took over from Steve McClaren last summer had caused a delay in resolving Viduka's situation, although one he hopes will not prove fatal.

He said: "Once a player goes into the last year of his contract, then he has the right to think about things. The longer it was left, he is then prepared to exercise that right.

"With it being my first year, I suppose I wanted to assess the squad in the early part of the season and I did not want to make a decision last summer on what I was going to do with players this summer.

"Perhaps that delay has slightly put us on the back foot a bit, but I needed to make sure I was making the right decisions on people.

"But that is how it has to be. If we had rushed into things previously, anything could have happened.

"But he knew we wanted him to stay - we made that clear in January when we had the opportunity to sell him if we had wanted to.

"Whatever happens with him, he has been brilliant for me as a manager. In my first season, he has been a real leader in the dressing room and on the field.

"I am very grateful for his contribution."