Cosham remain top of division two but look outsiders for promotion after a 2-1 loss as Uplands improved their chances of going up thanks to a Paul Savage double.
Uplands went close to an opener after eight minutes. Paul Rees launched a long throw into the box and keeper Steve Luke palmed away Savage’s glancing header.
After Uplands’ Jack Gregory had gone on a mazy run before firing wide, Savage powered another header past the far post.
It was all Uplands in the early stages and Cosham had to keep out a succession of corners before Luke turned away another Gregory effort.
But the goal Uplands deserved came on the half-hour mark. Justin Kemp swung in a free-kick from just inside the Cosham half and this time Savage arrowed his header inside the far post.
Cosham could have levelled straight after when Kye Haddigan beat several defenders before setting up Steve Mitchell, but the Dynamos’ top scorer elected to square the ball and the chance was lost.
Dynamos needed a much-improved second-half performance but Luke Hampson skied an early chance high over the bar and Matt Kirby got no power in a close-range effort.
Uplands were fortunate to remain ahead after 55 minutes. Hampson found Mitchell at the far post only for his half-volley to fly off target.
It was a far more even contest than the first half and after Gregory had stunned the palms of Luke, a Rian Taylor header glanced off the bar on 70 minutes.
But Uplands made it 2-0 in their next attack. Sub Curtis Woodhouse broke clear, squared to Savage, who side-stepped his marker and planted the ball high past Luke.
Cosham were looking short of ideas to get back in the match, with the Uplands defence dealing with their deliveries into the box.
And when Jack Atkins did have a free header, the ball finished two yards past the post.
Deep into injury-time, Cosham did finally net when Uplands defender Simon Mundy deflected a cross into his own net.
But it was too late to deny Uplands the victory.
Portsmouth Saturday League division two
COSHAM DYNAMOS 1 (Mundy og)
UPLANDS UNITED 2 (Savage 2)
SOUTHSEA UNITED 2
Goals from Godling and Haines put Southsea in the box seat for promotion after this victory.