As if further evidence were needed, Ivan Sproule demonstrated beyond a shadow of a doubt that he really is the nearest thing to greased lightning seen by Bristol City fans in many a long year.

Arguably the quickest player in the Coca-Cola Championship, the Northern Ireland international has been called upon to prove as much on two occasions in recent days.

First of all, he was challenged to a training ground race by new team-mate Izzy Iriekpen, after which the sprite-like winger was called upon to outstrip the entire Southampton team.

He showed both opponents a clean pair of heels, scorching clear of Iriekpen over 100 metres and then leaving breathless Saints for dead to score only his second goal of the season and secure a seventh win in eight games for a City side who are rapidly starting to look like genuine play-off contenders.

If City's challenge is taking on a more serious demeanour with every passing week, Sproule's stress-busting injury-time contribution at least gave nervous home supporters something to smile about.

Straining every sinew in a bid to cancel out Dele Adebola's 34th minute opener – the 150th of his career – the relegation-threatened visitors threw caution to the wind when awarded a corner a minute from time.

With nothing to lose and plenty to gain, every Saints player, including goalkeeper Kelvin Davis, pressed themselves into advanced positions in or around the home penalty area.

Imagine their chagrin when Robins keeper Adriano Basso claimed Andrew Surman's flag kick two-handed and hurled the ball over-arm to the waiting Sproule, who took possession just inside his own half.

What followed was pure comedy genius as the Irishman burst from the blocks with the ball at his feet, leaving a trail of utterly defeated opponents floundering in his wake.

At one stage, Sproule threatened to take too many touches and run the ball clean into the Atyeo Stand before correcting himself and steering it into an unprotected net to bring instant relief to an audience which had watched uncomfortably during a second half in which Southampton had threatened to discredit City's play-off credentials.

"Ivan has to be the quickest player I've ever worked with and has to be the fastest runner in the Championship," concluded Robins manager Gary Johnson.

"Once he received the ball from Basso, there was only ever going to be one outcome. Keith Millen (assistant manager) and I were jumping up and down and cheering when he crossed the halfway line, because we knew no-one would catch him.

"We were also laughing, because it looked at one point as though Ivan was going to continue running right off the pitch, down the tunnel and back into the dressing room. The dressing room attendant certainly thought so, because he stepped to one side when he saw him coming!

"But seriously, that was an important goal because it sealed victory for us and sent everyone home in a much happier mood than they might have been in had he not scored it."

Johnson revealed: "Izzy Iriekpen challenged Ivan to a race in training last Friday and I allowed them to do it, even though we had a game the next day and the physios were worried they might pull a muscle.

"To be fair to Izzy, he wasn't far behind after 100 metres, but I think Ivan was easing up."

No matter how invigorating Sproule's late intervention, his freakish goal could not disguise the shortcomings which subjected City supporters to a nail-biting afternoon.

Had Bradley Orr put away the penalty awarded the home side when Nicky Maynard was hauled down by Czech defender Rudi Skacel after 15 minutes, the outcome might have been different. But the right-back, successful from the spot against Norwich at Carrow Road a week earlier, fluffed his latest attempt and presented Davis with a comfortable save.

No matter. City still just about deserved the half-time advantage given them by Adebola's eighth goal of the season, the product of a perceptive ball over the top from Orr and a deft left-footed finish from a player more accustomed to scoring with his right.

Adebola and Maynard both squandered chances to increase the lead, while the outstanding Gavin Williams sent one shot fizzing wide from range and saw another expertly saved by a full-stretch Davis.

Otherwise, it was all Southampton. Second-from-bottom of the Championship, four points adrift of safety and without a win under new head coach Mark Wotte, these Saints proved difficult opponents.

Certainly, City were unable to subdue the counter-attacking threat posed by a team hell-bent upon victory at whatever cost. In almost complete control at Norwich seven days earlier, the Robins turned over possession far too readily against Southampton, who only had themselves to blame for a defeat which plunges them into deeper peril.

City players and supporters must have breathed a collective sigh of relief when shots from Morgan Schneiderlin and Jason Euell came back off the foot of Basso's left-hand upright, while the ubiquitous Williams was in the right place at the right time to hack a Jan-Paul Saeijs header off the line.

Encouraged by a City side which appeared incapable of retaining possession after the break, Wotte's team applied enough pressure to reduce a majority of those inside Ashton Gate to quivering wrecks.

Basso was equal to shots from Skacel and Marek Saganowski, but was thoroughly beaten when Euell was presented with a gaping target from just six yards with 15 minutes remaining. Fortunately for City, the striker somehow contrived to lift his shot into the Wedlock Stand, and his miss said much about why Saints are in trouble.

Just when anxious City fans thought they could take no more, up popped Sproule to provide welcome relief in the form of a comic book moment.