Albury Thunder's patchy ball control came back to haunt it against a powerhouse on Sunday.
Southcity tramped Thunder 36-10, scoring seven tries to two.
The league's leading try-scorer Jake Dooley notched another four to take his tally to 13 after only five games.
"He's quite deceptive, he's quite rangy, holds his feet quite well and brought the ball back well," Thunder coach Adrian Purtell said.
"They had a quality team, most of their players played well."
The home team raced to a 28-0 lead early in the second half, before the visitors' Curtly Jenkinson added some respectability with a try.
But tries to Josh Siegwalt and Dooley's last put the Bulls on target to reach the 50 mark.
However, Thunder steadied in the final 15 minutes with rugged prop Brad Hill posting the last try with nine minutes left.
Thunder went into the match in second place, on points differential behind Gundagai, but fell to third after the loss.
Purtell had said after last week's 38-12 win over Junee the team still had to improve its ball control against last year's grand finalists.
"I think our ball control again (let us down)," he said.
"You can't build pressure on teams, we were probably getting away with it the last couple of weeks with our errors and against a good team they'll hurt you and that's what they did."
Thunder also conceded tries in clumps, so they were never able to slow the Bulls' momentum.
Southcity posted three tries in a 12-minute period to finish the first half and then nabbed a double in four minutes in the second stanza.
"A couple of those were long range tries, we just didn't build enough pressure," Purtell said.
"I've got to put my hand up there, a couple of play five (last tackle) options weren't good enough."
The Bulls went into the game averaging 50 points over the first four rounds and while Thunder was able to keep the score well short of the half-century mark, it was realistically out of the match by half-time, trailing by 22 points.
"They're a good footy team, but we've got a high expectation of our team as well," Purtell said.
"That game was never going to define our season, but we need to improve for sure."
Thunder centre Ty Tindalevale was forced from the field with a hamstring complaint, so if he misses the home game against ladder leaders Tumut on Sunday it will stretch the outside depth of the Border outfit.
The Blues warmed up for the clash with a 32-12 win over Cootamundra.
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