Warrington Town came from behind to inflict a 3-2 defeat on South Shields as the Mariners endured a frustrating afternoon at Cantilever Park.
In-form Darius Osei fired Shields into the lead early on, but the hosts pegged them back in controversial circumstances shortly after the half-hour mark from the penalty spot.
An even second half swung the way of Warrington on 73 minutes when Matthew McDonald converted from close range, and when Sean Williams placed home a free-kick towards the end, the Mariners were left with too much to do.
They did pull a late goal back through Gary Liddle, with the defender's strike proving to be the last action of the game as the home side won by the odd goal in five.
Shields had won their previous three fixtures to climb to second in the Pitching In Northern Premier League, and named an unchanged line-up at Warrington.
But the hosts started the brighter, with Eddie Clarke forcing Myles Boney into a smart stop in the first minute.
The Mariners were dealt an early blow when Tom Broadbent was forced off with a leg injury within the first four minutes, but after an impressive spell from Warrington, Shields struck decisively in the 10th minute.
A Mackenzie Heaney free-kick was half-cleared but Shields kept the ball alive and early substitute Dillon Morse delivered a cross from the right of the area which Osei finished from close range as he notched his fourth goal in three appearances.
Warrington responded well to the setback and Boney was drawn into another fine save when he tipped a Bohan Dixon header over the bar.
Shields grew into the game and were beginning to take control when, just before the half-hour, Boney was adjudged to have tripped Dixon in the area and the referee pointed to the spot.
Boney and his team-mates were adamant that the goalkeeper had won the ball, but the protestations were fruitless and Stefan Mols converted the penalty to draw the Yellows level.
The Mariners had the better of the remainder of the first half and were unfortunate not to reclaim the lead as Joao Gomes pulled the ball across from the right and Heaney's low drive was superbly saved by the legs of home goalkeeper Mackenzie Chapman.
Shields were then left frustrated three minutes into stoppage time when the referee played an advantage before blowing for a free-kick to the Mariners just as Blair Adams ran through towards goal.
The second half was a tight affair, and the visitors had the first decent opportunity thanks to Heaney, who twisted and turned on the left flank and delivered a dangerous low cross which Osei was just unable to convert.
They were hit with a hammer blow at the other end as Warrington went ahead on 73 minutes, with Dixon's ball across the face of goal fired in by McDonald from close range.
Shields pushed for an equaliser but their efforts were hampered with four minutes left when Williams bent a free-kick into the bottom corner from 20 yards.
The away side did not give up, though, and had a strong penalty appeal waved away and a Martin Smith free-kick clawed away by Chapman before Liddle pulled a goal back five minutes into stoppage time with a terrific strike.
There was no time for any further action as Shields tasted defeat in the league for the third time this season.
They will be looking to respond on Wednesday when they travel to Radcliffe.
South Shields: Boney, Hunter, Adams (c), Liddle, Broadbent (Morse 4), Smith, Briggs (Ross 62), Osei, Gomes (Mongoy 74), Mottley-Henry, Heaney. Subs not used: Doherty, Alessandra.
Goals: Osei (10), Liddle (90+5).
Image: Kev Wilson.