In a tightly-fought contest, scores were equal at 24-all with 9 minutes remaining before Krisnan Inu scored a try in the corner to take the lead.
Roosters second rower Willie Mason looked certain to scored an equaliser with three minutes on the clock but the Eels showed great determination to keep Mason out and their season alive.
The Eels finally had some drive from their forwards, Nathan Hindmarsh and Daniel Wagon having strong hands in the go-forwards – both veterans finding the ground quickly in tackles and generating good ruck speed for Parramatta. The Eels had the lions share of possession and needed the advantage to build their confidence and try to find some attacking spark.
The Roosters made the most of their few chances, on most occasions the Sydney side visited the Eels 20m zone – they came away with points, many of their tries coming from impressive passing movements as opposed to their customary kicks. Mitchell Pearce and Braith Anasta keeping busy and looking dangerous with most touches of the football.
But for the Eels they just needed to win no matter what form it came in.
Helped by poor Roosters discipline, Parramatta built pressure through penalties gained and slowly found their feet as Brett Finch and new half Kris Keating generated a good combination. Finch and Keating made a point of running to the line and creating doubt in the Roosters defence, allowing the likes of Feleti Mateo to weave his magic from the forwards and generate some quality offloads.
The win sees the Eels come into 12th position on the NRL Ladder poised just 2 points outside the top eight, with four rounds left. Parramatta would more than likely need to win all remaining games to achieve a finals birth, todays win might just give the Eels the kick along they needed.
Assistant coach David Fairleigh did most of the talking today as coach Michael Hagan recovered from a bout of vertigo that hospitalised him on Friday.
Inu finished with 16 points as the visitors took full advantage of a 7-2 penalty count.
Nathan Hindmarsh, Joel Reddy and Joe Galuvao also scored tries.
Roosters winger Shaun Kenny-Dowall scored a double for the Roosters but was forced from the field midway through the second half with what could be season-ending medial ligament damage.
Amos Roberts and Sam Perrett also scored for the Roosters, who missed a chance to join Manly, Melbourne and Cronulla atop the NRL ladder and now sit fourth.
The Eels took the lead in the seventh minute after Hindmarsh scored from a Brett Finch bomb.
Inu put them out to an 8-0 lead with a 17th-minute penalty but the Roosters hit back three minutes later when Roberts latched onto a pin-point Braith Anasta grubber.
They then grabbed the lead in the 26th minute when Kenny-Dowall crossed out wide for his 14th try of the season.
Another Inu penalty got the Eels back within two before Reddy stole back the lead for Parramatta when he plucked another Finch bomb five minutes before the break.
Kenny-Dowall went in for his second shortly after the break and Craig Fitzgibbon converted from out wide to square it up at 18-all.
The game continued to sway as interchange forward Galuvao gave the Eels the lead again in the 53rd minute from a play that was kick-started by a brilliant run and flick pass from Feleti Mateo.
But, on the back of being awarded their first penalty in the 57th minute, the Roosters again hit back with Perrett stepping his way over the line and Fitzgibbon making it 24-all.
Both sides failed to capitalise on their chances until Finch spun a lovely ball to set up Inu in the 71st minute and the Eels repelled two late Roosters raids to keep their season alive.
The Eels face the in-form Wests Tigers on Monday Night as both teams try to keep their Top 8 campaigns in tact. For the Roosters they travel to meet the chart topping Melbourne Storm as they try to keep their Top 4 hopes alive for 2008.
PARRAMATTA 28 (J Galuvao N Hindmarsh K Inu J Reddy tries K Inu 6 goals)
SYDNEY ROOSTERS 24 (S Kenny-Dowall 2 S Perrett A Roberts tries C Fitzgibbon 4 goals)