If Newcastle United’s chances of avoiding relegation were previously limited, they can now be characterised as minimal. As another fixture slipped by without victory last night, a season that has had the tang of desperation about it since Kevin Keegan’s reluctant departure in early September was heading towards a juddering and jarring denouement.

No one can say it would be unexpected and for all that their supporters — as always — are the undeserving victims of catastrophic mismanagement, few would present it as a travesty of justice. Alan Shearer has restored a crucial bond between club and fans, but it is asking too much for miracles and if Newcastle’s many travails can be summed up succinctly, it would be thus: not good enough.

A game that had been presented as the most important in living memory finished in a goalless draw and while opportunities were created against Portsmouth, all of them were spurned; most recent wounds on Tyneside have been similarly self-inflicted. A deflating result could easily have been worse, with Richard Hughes heading on to the base of the left post as the match ticked towards maturity.

Shearer’s four matches to date have earned Newcastle a single goal and two draws, the second of which hoisted them on goal difference above Middlesbrough, whom they still have to play at home. Gareth Southgate, the Middlesbrough manager, was a spectator last night. Fulham will also travel to the North East, but it seems inconceivable that Newcastle can survive without a positive result away to either Liverpool or Aston Villa. They remain three points adrift of safety.

Having previously termed the Portsmouth match as “must win,” Shearer, naturally, accentuated the positive. “I don’t know if that’s going to be a good point or a bad point,” the manager said. “But there are going to be more twists and turns, and four games in football is a long time. We’ve got to stick in there and keep fighting. We will do.”

Yet the sound at the final whistle cannot have escaped Shearer’s notice: utter silence. An evening that began with a rousing rendition of The Blaydon Races, delivered by Graham Danby, the opera singer — whose description of Portsmouth’s travelling support as “f****** hopeless” was unnecessary — ended with the fabled fat lady waiting in the wings.

Shearer acknowledged a bitter irony. Having waited patiently to field Michael Owen, Mark Viduka and Obafemi Martins from the start of a match, he watched all three spurn clear-cut chances; respectively a one-on-one opportunity, a fine, sweeping move that led to the Australian shooting directly at David James and a volley mishit from seven yards.

“All three strikers had chances and missed and we’ve paid the price for that,” Shearer said. “I’m happy with the chances we created, but I’m not happy we didn’t take them. It’s ironic that the three players I’ve wanted up there have had a good chance each, but I still believe we’ll be in the Premier League next season. I’ll be keeping everything crossed that we will.”

Newcastle have not won at home this year; Owen has not scored at all since January. “Confidence in football is huge,” Shearer said. “When the team isn’t winning matches, you get into a habit. But if we keep creating chances for Michael, we know that one will go in. The one he missed, he would expect to put away.”

The tension was palpable, yet Shearer made a brave attempt to inject a note of levity as he waited for Mike Riley, the referee, to start proceedings. As a thin drizzle fell inside the stadium, Shearer turned to his dugout and asked: “Has anyone got an umbrella?” It was a sickly sort of joke. Newcastle did not require their own wally with a brolly; not even Wor Wally.

Heavy clouds will not dissipate soon. Shearer lost José Enrique, his sole left back, to a first-half injury, a strained hamstring, which will certainly keep him out of Sunday’s match away to Liverpool. “He’ll be scanned in the morning,” Shearer said, “but it’s a blow.” Damien Duff may again be required to deputise in defence.

Approaching half-time, Newcastle’s spirits were lifted. James was called on to repel a driven shot from Duff and, moments later, Viduka headed a fine cross from Nicky Butt over the crossbar. Martins was more profligate when he hacked at his effort. Owen missed, while Andy Carroll, a substitute, headed over. For the most part, Newcastle struggled to impose themselves on Portsmouth, who have not won away from Fratton Park in the league since their defeat of Sunderland in early November, but the point takes them seven clear of the relegation zone. Content to defend in numbers, smothering possession, they broke forward with speed.

Newcastle needed Steve Harper to provide them with respite on several occasions; the goalkeeper was by far their most accomplished performer. In a less forgiving mood, Riley could have awarded a penalty when Peter Crouch tripped over Fabricio Coloccini’s legs and there were several other moments of danger.

“I’m satisfied with a clean sheet and a point, but have a tinge of disappointment we didn’t get all three,” Paul Hart, Portsmouth’s caretaker manager, said. “Newcastle threw the kitchen sink at us, but we were disciplined. We have still got some work to do.”

So do Newcastle. And plenty of fretting.

Newcastle United (4-3-3): S Harper — H Beye, S Bassong, F Coloccini, J Enrique (sub: D Guthrie, 28min) — A Smith, N Butt (sub: J Gutiérrez, 71), D Duff — M Owen, M Viduka (sub: A Carroll, 64), O Martins. Substitutes not used: J Barton, P Lovenkrands, D Edgar, T Krul. Booked: Bassong, Carroll.

Portsmouth (4-5-1): D James — G Johnson, S Campbell, S Distin, H Hreidarsson — D Nugent (sub: J Pennant, 66), H Mullins, S Davis, R Hughes, N Belhadj — P Crouch. Substitutes not used: N Pamarot, J Utaka, M Cranie, Kanu, A Begovic, A Basinas. Booked: Hreidarsson, Johnson.

Referee: M Riley.