Fullback Nathan Gardner has scored four tries as Cronulla came from 10 points down to defeat Souths 22-16 and claim its first Toyota Cup victory of the year.

The Sharks trailed 16-6 early in the second half before scoring 16 unanswered points to pull off a remarkable win.

The last of Gardner's four tries gave the home side the lead for the first time just four minutes shy of full-time.

South Sydney was on the board early, crossing through Hayden O'Donnell just seven minutes in.

Adam Reynolds converted for a 6-0 lead.

The Rabbitohs were on the board again 10 minutes later, captain Nathan Peats forcing his way over from dummy half.

Reynolds landed the simple conversion and the Bunnies had skipped out to a handy 12-0 advantage.

The Sharks needed a try to stay in touch and Gardner answered their prayers midway through the half.

With Chad Townsend adding the extras, the Sharks were back in it at 12-6.

But just four minutes after the resumption Souths had their third try.

A lovely cut-out pass from Matt Mundine sent winger Tim Bennett over in the corner to make it 16-6.

Gardner gave Cronulla a lifeline with a terrific solo try in the 56th minute.

The fullback dummied before taking on the defence close to the line and crashing over.

The conversion from out wide went astray, leaving the Sharks trailing 16-10.

Gardner completed his hat-trick with 15 minutes to go to put the hosts right back in the contest.

The classy No 1 toed the ball ahead twice and kept his composure to flop on the bouncing ball and draw the Sharks to within two.

Townsend dragged his conversion wide but it was the start of a full-blown revival.

Gardner's fourth try – in which he shaped to pass and sped through a gap to cross out wide – put Cronulla in front 18-16.

Kyle O'Donnell put the icing on the cake when he took on the defence and crashed over out wide with 95 seconds remaining.

The Sharks now have a win, draw and loss from their three games.