The Waratahs have withstood a late onslaught from a desperate Sharks line-up to post an unconvincing 25-21 victory in slippery conditions at the Sydney Football Stadium on Saturday night.
Despite enjoying a two-man advantage midway through the opening stanza after two Sharks players were issued with yellow cards, the hosts somehow trailed on the scoreboard before tries to Daniel Halangahu and Tom Carter saw them take a slender lead into the interval.
Chris Hickey's men threatened to run away with the contest when man of the match Tatafu Polota-Nau scored early in the second half, but the Sharks, winless in their first three games of the campaign, hit back through Springbok centre Adrian Jacobs to close within four points with 25 minutes on the clock.
The visitors were clearly the stronger side in the final quarter and looked destined to steal the points when Kurtley Beale was sin-binned for a deliberate knock down that denied them an almost certain try in the 78th minute.
But the lacklustre hosts were granted a reprieve when referee Paul Marks controversially penalised the visitors for obstruction in the final lineout of the contest to hand the Waratahs their second win of the campaign.
The defeat leaves the Sharks' season in tatters while the Waratahs now sit mid table on nine competition points through four rounds.
Berrick Barnes' early penalty was cancelled out by a long-range drop goal from former England international Andy Goode in the fourth minute of play.
Barnes added another three points soon after but the Sharks again drew level on 17 minutes when Goode slotted a penalty goal after a sustained attacking raid from the visitors.
Momentum swung firmly in favour of the Waratahs when Sharks prop Jannie du Plessis was yellow carded for tripping Halangahu in the 21st minute before Goode joined him in the sin bin three minutes later after a professional foul.
But the Waratahs, who produced six handling errors in the opening 30 minutes of the match, inexplicably failed to cross despite their two-man advantage.
And the Sharks made them pay when explosive No.8 Ryan Kankowsi swooped on a terrible pass from Luke Burgess and sprinted 50 metres to put the visitors ahead 11-6 after 26 minutes.
Ruan Pienaar increased the buffer with a penalty goal on the half-hour after Kankowski almost scored his second try moments earlier.
Pienaar quickly turned villain when he allowed the ensuing kick-off to bounce to gift the hosts ideal field position.
It wasn't pretty but the Waratahs finally took advantage of the extra man when Halangahu crashed over for a converted try to cut the deficit to a solitary point before Carter restored the lead.
A lack lustre start to the second half attracted boos from sections of the crowd, but they had reason to cheer when Polota-Nau torpedoed over the line 11 minutes in, with Barnes adding the extras for a 25-14 lead.
But a badly botched re-start from the Waratahs let the Sharks back into the contest, as Adrian Jacobs crossed untouched after a sustained attack, to trim the deficit to four points with 25 minutes remaining.
Waratahs 25
Tries: Halangahu, Carter, Polota-Nau
Cons: Barnes 2
Pens: Barnes 2
Sharks 21
Tries: Kankowski, Jacobs
Cons: Goode
Pens: Goode, Pienaar
Drop goals: Goode
@ Sydney Football Stadium, 6/03/10. Crowd: 20,651