The Waratahs secured a 29-12 bonus point Super Rugby victory over the Lions at the Sydney Football Stadium on Saturday.
The victory keeps the Waratahs in the top six and on track to qualify for the play offs starting next month.
The Waratahs scored five tries in the first half and looked to have turned a corner as they played exciting rugby but slipped back into their "ugly" game in the second half and failed to score a second half point.
The first Waratahs try was scored in the second minute by Kurtley Beale and Soseni Anesi scored his first and second Super Rugby try of the season. Tries from Ryan Cross and Tom Kingston put the Waratahs firmly in control of the match.
After trailing 29-5 at half time the Lions played all the rugby and scored the only points of the second half and won it 0-7 due to the Waratahs insistence on aimless kicking.
The Lions, with two wins in 13 matches, were coming off an upset victory last week over the Brumbies in Canberra.
They leveled the match at 5-5 quickly, but two tries to Sosene Anesi and another to Ryan Cross gave the Waratahs a four-try bonus point well before halftime.
Replacement Tom Kingston scored the fifth try for the Waratahs inside the first 40 minutes and they led 29-5 at the break.
Lions replacement Dylan Des Fountain scored the only try of a dour second half with 10 minutes left.
The Waratahs, who stayed in the top six overall with the win, were content to retreat into a defensive shell, kicking instead of looking for possession.
It was their 10th straight win over the Lions.
Moments after kickoff, Beale put Lachie Turner away down the right wing with a crisp pass and backed up on the inside to score out wide.
The Lions briefly drew level in the 14th with a try to fullback Jaco Taute, who won the race to the ball after a Butch James grubber kick into the Waratahs' in-goal area.
After a midfield pass from prop Sekope Kepu, Beale sped through to take Berrick Barnes' well-executed cross-field kick and then floated a ball over for Cross to score out wide.
Beale slotted the conversion to make it 17-5 and, as a bonus, the Lions were reduced to 14 men for 10 minutes when lock Deon Van Rensburg was sin-binned for kneeing New South Wales captain Dean Mumm in the head in a preceding ruck.
The Waratahs capitalized on their advantage with Anesi swooping on a Luke Burgess box kick to grab his second try of the night.
Mumm defended his side's second-half tactics.
"I think the first half was pretty pleasing," Mumm said.
"In the second half, we had to look to relieve a bit of pressure, and the Lions' defense was very tough."
The Lions were not helped by 11 missed tackles in the opening half and captain Doppies La Grange said his side was "not physical enough."
"I think we stayed in neutral, maybe a little bit backwards," he said of the team's progress after its win last week over the Brumbies.
"We weren't clinical tonight like we were last week."
The Waratahs leave on Sunday for a two-match South African trip to play the Sharks in Durban and the Bulls in Pretoria.
The Lions play the Highlanders in Dunedin on Saturday.
Final Score Waratahs 29 Lions 12
Tries - K Beale, S Anesi 2, R Cross, T Kingston.
Con - K Beale 2
Tries - J Taute, D. Des Fountain
Con - E Jantjies
Cards - D van Rensburg (26th min) yellow
Referee: Marius Jonker
Ass. Ref. 1: Angus Gardner
Ass. Ref. 2: James Leckie
TMO: Matt Goddard
Waratahs : 15. Kurtley Beale , 14. Lachie Turner , 13. Ryan Cross , 12. Tom Carter , 11. Sosene Anesi , 10. Berrick Barnes , 9. Luke Burgess , 8. Ben Mowen , 7. Chris Alcock , 6. Dave Dennis , 5. Sitaleki Timani , 4. Dean Mumm [c] , 3. Sekope Kepu (Randwick) , 2. Tatafu Polota-Nau (Parramatta) , 1. Benn Robinson
Reserves , 16. Damien Fitzpatrick, 17. Al Baxter , 18. Kane Douglas , 19. Hugh Perrett , 20. Brendan McKibbin , 21. Daniel Halangahu , 22. Tom Kingston.
Lions : Jaco Taute, Lionel Mapoe, Alwyn Hollenbach, Doppies la Grange (capt.), Deon van Rensburg, Butch James, Jano Vermaak, Josh Strauss, Michael Rhodes, Derick Minnie, Franco van der Merwe, Wikus van Heerden, Patric Cilliers, Bandise Maku, JC Janse van Rensburg.
Replacements: Edgar Marutlulle, Jacobie Adriaanse, Warren Whiteley, Cobus Grobbelaar, Rory Kockott, Elton Jantjies, Dylan Des Fountain.