Nigerian Ayegbeni Yakubu, 24, international headed for Everton yesterday after the two clubs finally agreed an $28million fee.

He is expected to seal his move within hours, leaving Southgate just eight days during which to find a replacement armed with a proportion of the cash his club will recoup on their $19million investment two summers ago.

Southgate has identified targets during the summer, all the time knowing that, despite his insistence that the former Portsmouth frontman was not for sale, his departure was always a possibility.

With last season's top scorer Mark Viduka having already left for Newcastle after rejecting a new deal, he knows he must move swiftly to replace the 35 goals the pair scored last season.

The Teessiders have invested £8million in Tottenham's Mido and Arsenal's Jeremie Aliadiere this summer, with Tuncay Sanli also arriving on a free transfer from Fenerbahce to join South Korea international Dong-Gook Lee.

However, Tuncay has played his football at the Riverside Stadium to date in a withdrawn role, while Aliadiere and Lee are yet to open their accounts.

Boro have scored three goals in as many games so far this season, only one of them coming from a striker when Mido scored on his debut at Fulham last Saturday.

Southgate is confident all four men will find the back of the net given time to adjust to their new surroundings, but the addition of a proven prolific goalscorer is a must with Yakubu having contributed 19 and 16 respectively during his two seasons on Teesside.

Boro insisted last night they are yet to table any formal bids as they await the completion of the Nigerian's deal, although they have been busily assessing potential targets for some time.

High on the list is Heerenveen's Afonso Alves, who scored 34 goals in 31 appearances last season, although the Teessiders have dismissed reports they have already made an offer for the Brazilian.

They have also been linked with CSKA Moscow's Vagner Love and PSV Eindhoven's Arouna Kone, while Lyon frontman Fred and Benfica striker Nuno Gomes have also been mentioned.

But Boro have prided themselves on the depth of their research this summer and it would be no surprise if they have other targets elsewhere.

Ironically, Southgate and his players will enjoy an early reunion with Viduka on Sunday when his new club Newcastle head down the A19 looking for revenge for last season's 1-0 defeat at the Riverside, courtesy of Yakubu's late header.

Midfielder Lee Cattermole, whose winner at Fulham last weekend handed the club their first win of the season, has fond memories of the derby clash having made his full debut at St James' Park two seasons ago.

He knows what a miss Viduka will be, and insists there will be no hard feelings over his decision to join the Magpies.

Cattermole said: "Mark Viduka was a great player to play with and I wish him all the best.

"He made the decision to move on, but that's football and if I get the chance to talk to him, I will."