Toby Greene's brilliant four-goal first half has helped fire the GIANTS to a stunning seven-point upset of Geelong, putting another dent in the Cats' flagging premiership defence.

GIANTS captain Greene starred early, with former skippers Stephen Coniglio and Callan Ward also significant contributors in the gutsy 12.9 (81) to 10.14 (74) victory at GMHBA Stadium.

It was the GIANTS' fourth win under first-year coach Adam Kingsley, helping Greene celebrate his 200-game milestone in fine style while improving their record to 4-7.

The shock result inflicted more pain on injury-hit Geelong (5-6), who have now suffered three-straight defeats for the second time this season.

Tall defender Esava Ratugolea is the Cats' latest injury concern after being substituted off with a hamstring concern.

Greene kicked 4.1 from seven disposals in the first half while Jake Riccardi and Brent Daniels both finished with three goals, including two crucial majors each in the final term as the GIANTS held off a huge late challenge.

The GIANTS led by 24 points at the eight-minute mark of the last quarter but Geelong stormed back into the contest, roared on by a vocal home crowd of 21,349.

The Cats kicked four of the next five goals and twice trimmed the margin to two points before Daniels shut the gate from close range with little more than two minutes left.

Coniglo (26 disposals, seven clearances), Ward (19, seven), Tom Green (28, three) and Lachie Ash (26, two) were outstanding, while Lachie Keeffe limited Cats spearhead Tom Hawkins to one goal from 10 disposals.

Geelong became the first club in AFL/VFL history to field three Irish players in the same team when Oisin Mullin made his debut alongside Zach Tuohy and Mark O'Connor.

Speedster Mullin showed glimpses and almost kicked a brilliant goal, spinning out of a tackle by the Giants' own Irishman Callum Brown before his snap shot floated narrowly wide.

He was also caught holding-the-ball by Greene, who wheeled off the mark to kick a stunning goal from 50 metres during the second quarter.

The GIANTS kicked 4.2 to 1.2 for the term - three of those from Greene - to take a 17-point lead to the main break.

The GIANTS looked home when it broke out to a game-high 24-point lead early in the final term.

Tyson Stengle and Ollie Henry kicked two goals each to drag Geelong back into the contest, bringing the home crowd to life.

But Daniels' last goal steadied the GIANTS, who hung on in a thriller.

Tom Stewart (31 disposals) was Geelong's major ball-winner, with Mark Blicavs (22 touches, seven clearances) and Tom Atkins (20, six) also busy.

The Biggest GIANT of Them All

It's been a long journey to 200 games for Toby Greene, but never a dull one. The GIANTS superstar lined up in the GIANTS' first side to take to an AFL field in round one, 2012, after being selected with pick 11 in the previous draft, but he's missed a total of 68 games since then through injury and - a little too often - suspension. However, there's never been any doubting Greene's importance to his side and he underlined his superstar status again on Saturday with four first-half goals proving the difference. Toby didn't get to five but his leadership, and the fact Geelong's defence couldn't give him an inch, created the opportunities that teammates were only too happy to make the most of.

GEELONG                                    2.4    6.5    6.9    10.14 (74)
GIANTS                                        
 2.3    3.6    8.9    12.9 (81)

GOALS

Geelong: Cameron 2, O.Henry 2, Stengle 2, Parfitt, Hawkins, Close, J.Henry
GIANTS:
Greene 4, Daniels 3, Riccardi 3, Briggs, Bedford

BEST

Geelong: Stewart, Miers, Smith, Blicavs, Cameron
GIANTS:
Greene, Daniels, Green, Whitfield, Hogan, Coniglio

INJURIES

Geelong: Ratugolea (hamstring)
GIANTS:
TBC

SUBSTITUTES:

Geelong: Mitch Knevitt (replaced Esava Ratugolea in the third quarter)
GIANTS:
Josh Fahey (replaced James Peatling in the fourth quarter)

Crowd: 21,349 at GMHBA Stadium