Campbelltown stayed on course for a finals' berth in their comeback season with a 33-15 defeat of a tenacious Tech Waratahs on Saturday at Saunders Oval.

Shrugging off a shoddy first-half display, the Harlequins crossed for four tries in the second half, preventing Tech Tahs captain-coach Tim Olsen from celebrating his 300th game with a win.

"It was always going to be a hard slog here," Campbelltown coach Owen Gregory said.

"They're a tough side when they're at home and for us to come out and win the way we did in that second half, I'm very proud of the boys."

Tech Waratahs took advantage of a Quinnies error with a try after two minutes.

The visitors hit back with a converted try for a 7-5 lead, but the Tahs pinched another try to forge ahead 10-7 at half-time.

Campbelltown were a different side in the second stanza, taking control with two quick tries for a healthy 21-10 lead.

It quickly became 28-10 before Tech Tahs scored in the corner with 10 minutes remaining.

The Quinnies had the final say with a late try.

"We didn't start that well," Gregory said.

"That first 10 minutes, they were in the game 100 per cent. They dominated it and we needed to turn it around in the second half. We just needed to go back to our game plan.

"There was too many mistakes in it and it was costing us points. Once we turned that around, we started to build a bit of momentum and move forward."

Premiers in 2001, the Quinnies joined the Sydney Suburban competition in 2003, staying for 11 seasons before re-aligning with Illawarra this year.

They opened 2015 with five straight wins before losing key players to injury and copping consecutive thrashings from Avondale (45-0) and Kiama (50-0).

But wins over Shoalhaven and the Tahs have got the Harlequins back on track for the play-offs.

"We're not worried about the semis at the moment. We haven't even mentioned the semis to our guys," Gregory said.

"Our focus is all about keeping it calm and collected at the moment. We still have six guys out and three of those should be back in two weeks.

"We're slowly building and we just have to keep that momentum going. Consistency is a big thing in rugby and if we can play with that consistency every week we'll go a long way."

The last-placed Tahs won their first game of the season the previous week against Bowral and were heading for a second win at half-time on Saturday.

Olsen said his side was simply out-classed in the second half.

"We had a dream start but they just came back. They showed their resolve as a good side and the scoreboard tells the story," he said.

"They stayed in the contest longer than we did. We relaxed at times and made errors and they capitalised. They sit where they are on the table for a reason."

Olsen said his side gave everything in his milestone game.

" That's the best game we've played all year, without a doubt.

I just wanted a good effort from the boys and that's what I got. I'm proud of them."

In other games, Avondale smashed Bowral 55-7, Kiama beat Shamrocks 41-3, and Shoalhaven snuck home to beat Vikings 30-19.

University demolished Camden 45-3 in Friday night's grand final re-match at University Oval.