Harry Redknapp will wait until Thursday before giving up his striker hunt.
The transfer window closes next Monday but Redknapp is at the end of his tether after a fruitless trip to Spain last week.
Celta Vigo's Ivan Olonso was the man he went to watch - but Redknapp returned to Pompey a disappointed man.
He said: "What can you do when an agent tells you about a fantastic striker, so you go and watch him play only to find that he's on the bench and plays the last 20 minutes on the left wing?!
"I can't imagine Arsene Wenger or Sir Alex Ferguson putting up with that. I found myself stuck outside a hotel in Alaves in the early hours of the morning, trying to flag a taxi in the p*****g rain.
"I had to ask myself what I was doing - I can't afford not to do it. I'll still visit another two or three countries this week to try and get someone in but, if I haven't got anyone by Thursday, that will be it."
Hungarian striker Attila Tokoli failed to impress during his trial last week, leaving Redknapp in urgent need of a front man before Saturday's visit from fellow strugglers Wolves.
Patrik Berger and Kevin Harper had to take turns as makeshift strikers alongside Teddy Sheringham against Scunthorpe as Mark Burchill (knee), Lee Bradbury (broken ribs), Vincent Pericard (thigh) and Deon Burton (knee) are all injured.
So, until Yakubu returns from African Nations' Cup duty with Nigeria, youth team striker Warren Hunt is the only striker at Redknapp's disposal other than 37-year-old Shering-ham.
"Teddy should have been rested against Scunthorpe. He needs a day off but has had to keep going because of the situation we're in," added Redknapp.
"All I can do is give it my best shot, hope that we get by until Yakubu gets back, but it's difficult to get anyone of Premiership quality in on a free or a loan.
"And, from what I've seen, there doesn't seem to be much difference in quality between a striker who costs £2m and one available for nothing."
The shortage of strikers meant that Matthew Taylor's first goals since September were greeted with relief from the Pompey dug-out.
Taylor's second, a smart first-time finish from 16 yards, turned out to be the winner after substitute Andy Parton volleyed past Shaka Hislop with a minute to go.
Hislop had denied Scunthorpe striker Paul Hayes from point-blank range early in the second half and then clawed away a corner from the evergreen Peter Beagrie before the visitors got the goal they deserved.
Parton capitalised on a static Pompey backline to set up a frantic finale and Redknapp added: "It was always going to be difficult for us with no front men. Scunthorpe could easily have equalised but there's no easy game in this competition - look at Chelsea at Scarborough."
Redknapp's best news of the day was seeing Amdy Faye, "a top, top player", play the last 20 minutes with no reaction to the knee injury that has kept him out for the last six weeks.
For Scunthorpe, it was the financial boost that they will get from their share of a 17,508 crowd that paid £25 each for the privilege of watching a largely uneventful FA Cup fourth- round tie.
It was certainly a happier experience for Scunthorpe boss Brian Laws than the last time he was at Fratton Park in this competition.
Eleven years ago, Laws was sent-off as Pompey beat Nottingham Forest 1-0 in an FA Cup quarter-final.
He said: "I thought we were the better side in the second half. The second goal was the nail in the coffin for us but, apart from the goals, Portsmouth didn't really hurt us.
"My players didn't let their heads drop and our goal made it a very interesting last couple of minutes, but the difference between the sides was the qaulity of the finishing.
"We were guilty of naive defending for the second goal - you can't afford to give Premiership players time and space, and Paul Hayes didn't score for us when he was put through early in the second half.
"You have to take chances like that."
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