Yakubu was on target for Middlesbrough to deny former club Portsmouth victory.
Boro's £7m summer buy from Pompey headed home at the far post after 53 minutes to level Gary O'Neil's effort just a minute after the break.
Half-time substitute Svetoslav Todorov made a vital first contribution, pulling the ball back for O'Neil to score from only eight yards.
Substitute Mark Viduka and Yakubu then both had chances to give Boro victory, but Pompey deserved a crucial point.
The first 45 minutes was a grim affair, with both sides struggling to create any opportunities in a strangely subdued atmosphere.
Yakubu gave Portsmouth a scare when he got on the end of George Boateng's cross but was unable to keep his header down.
But Portsmouth also had their moments, and they almost took the lead after 28 minutes when Laurent Robert's cross was only inches away from finding Dario Silva at the far post.
Silva was replaced by Todorov at the interval, and he played a part as Pompey took the lead after 46 minutes.
The injury-plagued Todorov crossed from the right, and when Zvonimir Vukic missed his chance, the ball fell invitingly for O'Neil to sweep a close-range finish past Mark Schwarzer.
The lead lasted only eight minutes before Yakubu punished Pompey, taking full advantage of poor defending to direct Fabio Rochemback's corner past Jamie Ashdown at the far post.
Boro boss Steve McClaren made an instant double switch, sending on Mark Viduka and Jimmy Floyd Hasselbaink for Rochemback and Massimo Maccarone.
And Viduka almost carved out an opportunity for himself after 65 minutes, turning neatly in the area only to shoot straight at Ashdown.
Yakubu almost doubled his tally three minutes later, firing inches wide with Ashdown beaten.
Ashdown then produced a fine diving save injury-time to deny Boateng a winner from 18 yards.
Middlesbrough manager Steve McClaren:
"We were poor in the first half very passive.
"Second half, we upped the tempo and had a go. I thought on chances we could have won the game.
"We are disappointing at home. We need a win from somewhere. It's the same old problem of consistency and we have to find answers for that."
Portsmouth boss Alain Perrin:
"I'm a little bit disappointed because we led 1-0 but we have won a point against a good team and it is a good result.
"It was difficult to start with for Gary O'Neil because of international duty but after that he got better and better.
"Now, before big games against Chelsea and Manchester United we need to take points at home."
Middlesbrough: Schwarzer, Parnaby, Riggott, Southgate, Pogatetz, Maccarone (Viduka 55), Doriva, Boateng, Queudrue (Mendieta 45), Rochemback (Hasselbaink 55), Yakubu.
Subs Not Used: Bates, Knight.
Booked: Pogatetz, Boateng.
Goals: Yakubu 54.
Portsmouth: Ashdown, Stefanovic, O'Brien, Priske, Griffin (Skopelitis 45), O'Neil, Viafara, Vukic, Taylor, Silva (Todorov 45), Robert (Vignal 58).
Subs Not Used: Westerveld, Songo'o.
Booked: Skopelitis, O'Neil, Vignal.
Goals: O'Neil 46.
Ref: C Foy (Merseyside).