NRL leaders Parramatta Eels produced a storming second-half fightback to beat Penrith Panthers 16-10 after New Zealand Warriors downed North Queensland Cowboys on Friday.

Penrith were 10-0 up until just after the hour mark in the battle of the west at Bankwest Stadium, first-half tries from Brian To'o and Josh Mansour putting them on course to go top of the ladder.

The Eeels clicked into gear in the final quarter, though, with the influential Waqa Blake, Clinton Gutherson and Ryan Matterson going over to maintain their perfect record.

Parramatta are three points clear at the summit after winning five out of five at the start of a season for the first time since 1986, while Penrith's loss was their first of the campaign and Kurt Capewell also suffered a medial ligament injury to his knee.

To'o crossed for the opening score midway through the first half and Mansour finished off a slick move on the left flank four minutes prior to the interval, with Nathan Cleary converting.

It was Blake who got the Eels back into a contest watched by a limited number of members and corporate guests, charging over before laying on a score for Gutherson.

Parramatta had three tries in the space of six minutes when Matterson benefited from a kind bounce of the ball to dot down, Mitchell Moses adding the extras for a second time and Brad Arthur's men defending for their lives to win a thriller.

Peta Hiku grabbed a hat-trick as the Warriors scored seven tries in a 37-26 defeat of the Cowboys at Central Coast Stadium earlier in the day.

Kodi Nikorima also sparkled for the Warriors, while North Queensland lost Valentine Holmes and Jordan McLean to injuries as they slumped to a third defeat of the year despite 14 points from Kyle Feldt.