Eric Anabalon?s goal-line tap in from Ryan O?Shea?s powerful header was enough to give Penrith the win and cement a position in the top five for United.
Sydney Olympic will feel aggrieved at having come away from the game with nothing after spending most of the match probing for clear chances.
In an even first-half Sydney Olympic almost opened the scoring after 8? minutes when Michael Cindric rose above the defence but headed straight at keeper Schwarzer.
Then in Penrith?s first real attack Carl McNaughton was heading goal-bound but his shot was smothered by the defender and keeper.
After weathering Olympic?s early possession Penrith had another good chance when Javier Mancino?s diagonal run found Nick Tsattalios at the edge of the box his shot evaded keeper Michael Herbert and the Penrith Nepean midfielders sliding in at the far post.
Olympic?s raids were coming mostly from the flanks with Shannon Cole playing well and supplying good balls to the frontline, which weren?t being converted.
After 27? minutes United had another breakaway opportunity when Carl McNaughton latched onto a loose pass but his effort was brilliantly saved by keeper Michael Herbert.
Shannon Cole carved out yet another opportunity, his low cross found its way to the far post. Anthony Doumanis? attempt was blocked but the rebound fell quickly to James Kovas who guided the ball past Schwarzer but went agonisingly wide.
Deep in first-half injury time Penrith won a corner on the right. From the cross substitute Ryan O?Shea attacked the ball hard and his downward header was tipped over the line by Eric Anabalon with almost the last kick of the half.
In the second-half Olympic came out with renewed vigour to get back into game, but without the influential wing-back Shannon Cole who was injured in a tackle shortly before half-time.
Michael Cindric again went close with a header this time flashing just wide of the post. After 60?mins a cross from the right was missed by the keeper this led to a goalmouth scramble which Nepean cleared.
In the 69? minute Nathan Sherlock played a nice one-two with James Kovas but his shot went wide. United?s organised defending was beginning to frustrate Olympic as they dropped back deeper in defence to defend their goal.
Despite this, Penrith had the one real chance of the second-half when Willy Stuart broke down the right and curled a nice shot just wide of goal.
Penrith had now retreated to their penalty box and their stout defending in the middle which had forced Olympic wide all game was limiting Olympic?s options.
In the 83? minute Daniel Schwarzer made an excellent save from Olympic?s Chris Triantis.
The officials then waived away a penalty appeal when Anthony Hartshorn?s shot was deflected by a defender.
In the dying minutes United had Luke Boyd to thank when he headed clear a goal bound attempt from a determined run from Mirko Jurilj.
Penrith coach Abbas Saad agreed it was their all round teamwork that earned the win. But he did mention the 3 one-one chances not converted in the first-half.
He was delighted for his boys saying his full backs Willy Stuart and Nick Tsattalios were key to the win because the game became so congested in the middle.
Sydney Olympic will be disappointed they didn?t carve out more chances in the second-half, and the loss of Shannon Cole at half-time certainly didn?t help their cause.
Abbas said their aim was to feature in finals football this year and now sitting in fourth position on the table they are on track to achieve their goal.
Sydney Olympic 0
Penrith-Nepean United 1 (Eric Anabalon 44?)
Venue: Belmore Sports Ground
Referee: A. Stribinger
Assistant Referees: D. Fuda, D. Goldsmith
Fourth Official: N Tragoustis
Sydney Olympic: 1. Michael Herbert; 4. Mirko Jurilj, 5. Michael Cindric (18. Chris Triantis 70?), 6. Roger Galayini, 7. Milorad Simonovic, 9. Anthony Hartshorn, 10. Anthony Doumanis (19. Mario Musumeci 58?), 12. James Kovas, 14. Shannon Cole (11. Carlo Musumeci 45?), 16. Nathan Sherlock, 22. Peter Zorbas
Substitutes not used: 17. Iain Ramsey, 20. Sam Emmanouil
Penrith-Nepean United: 42. Daniel Schwarzer; 9. Carl McNaughton, 11.Eric Anabalon, 7. Javier Mancino, 5. Luke Boyd, 16. Michael Cromar, 3. Nick Tsattalios (15. Angelo Martino 76?), 17. Ozgun Kanyilmaz (4. Ryan O?Shea 40?), 10. Tayfun Buyukkopru (23. Devrim Huseyin 67?), 2. Willy Stuart, 28. Ante Juric
Substitutes not used: 1.Chad Taylor, 18. Shannon Bergin
3 – Ryan O?Shea (PNU)
2 – Willy Stuart (PNU)
1 – Michael Herbert (SO)
-By Peter Davies