The south coast club went down without kicking a ball on the day, any flickering hopes of survival finally snuffed out by West Ham United beating Sunderland 1-0.
In truth, their chances had already been effectively killed off when they were docked nine points for going into administration in February.
With West Ham moving four points clear of the drop zone, Portsmouth are mathematically unable to escape with five matches remaining. The result ended Pompey's seven-season stint in the top flight.
In the only other Premier League game of the day, Burnley trounced Hull City 4-1 in a battle between the two sides most likely to follow Portsmouth down to the Championship.
Both have 27 points with Wigan Athletic and West Ham on 31. Portsmouth have 14. On the flip side, West Bromwich Albion secured their promotion back to the top flight, joining Newcastle United, after beating Doncaster Rovers 3-2.
Brazilian striker Ilan sealed Portsmouth's fate with a 51st minute strike, his second goal in as many games bringing a smile to the face of manager Gianfranco Zola.
"I am really delighted for the players and everybody involved with West Ham," he told Sky television. "We've gone through a difficult time. It's still not easy, but a little bit better."
Portsmouth fans can hope to have their spirits lifted again at Wembley, where the Pompey Chimes are sure to sound out again on their return to the stadium where in 2008 they ended a 58-year wait for a major trophy.
CRISIS MANAGEMENT
The 112-year-old club, English champions in 1949 and 1950 as well as twice FA Cup winners, have lurched from crisis to crisis since that epic victory and are still seeking a saviour with debts of around 70 million pounds .
The first Premier League club to go into administration have been through four owners and as many managers in the last two years, with Israeli Avram Grant the last to take on the impossible task of keeping the club up.
Put up for sale by Alexandre "Sacha" Gaydamak last August, United Arab Emirates businessman Sulaiman al-Fahim stepped in before selling on to Saudi Ali al Faraj.
Hong Kong businessman Balram Chainrai became the fourth owner in less than a year, saying he had "zero interest" in running the club and hoped to offload it as soon as possible.
Gaydamak's father Arkady, a Russian-Israeli businessman, was convicted by a French court last year of illegal arms deals, tax fraud, money laundering, embezzlement and other crimes.
"The adverse publicity surrounding Sacha's father sent the banks who provided us with overdraft facilities into meltdown," former chief executive Peter Storrie said in February.
"Overnight we had to find nearly 50 million pounds as well as sustain the running of the club."
On the pitch, the situation was equally troubled with Portsmouth losing their opening seven matches of the season and struggling to pay player
