Alessandro Del Piero was the star for Sydney FC in what could be his second last home match for the side as he scored a brace, to make life hard for the seventh placed Jets.
There was a big chance of the match being delayed, with the heavy rain in Sydney on Sunday creating a waterlogged pitch, but a pitch inspection allowed the match to go ahead with the match.
The rain stopped, which saw the match start to be played, but both sides struggled to take control on a tough pitch, fittingly ten years on from the last ever NSL Grand Final played in very similar conditions.
The two sides still struggled to get going in the opening stages, with lots of pools of standing water making play difficult for both teams, who still tried to attack.
Del Piero forced a good save out of Glen Moss in the tenth minute after a counter attack that was launched by Sydney keeper Vedran Janetovic.
Wellington could well have had the lead in the 14th minute, and if not for some desperation from Janjetovic they would have been as Carlos Hernandez switched for Jeremy Brockie, who cut in to the box, and shot, which skimmed off the water, nearly catching out janjetovic, who got down to smother the ball.
Moss had to be at his best in the 25th minute to keep Sydney out as Del Piero played Joel Chiansese through, forcing a save out of Moss, who recovered and held on to Milos Dimitrijevic’s follow up effort.
There was controversy in the 33rd minute as Brockie fouled Del Piero outside the box, but the veteran made sure to fall inside the box, fooling Kris Girffiths-Jones in to awarding a penalty, that he picked himself up to take and score.
That decision saw tempers flare and just two minutes later scramble in the box resulted in two little skirmishes, that saw one man from each side issued yellow cards.
Janjetovic was probably lucky to stay on the park after the fourth official picked up his punch on an opponent but was only shown a yellow card.
Right at the death of the first half Sydney were at it again as Richard Garcia was fouled by Ben Sigmund, allowing Del Piero to step up and hit a beautiful free-kick that curled over the wall and in to the top left hand corner of the net.
Eight minutes in to the second half Del Piero could well have made it three as he hit a free-kick from a similar position, but hit the corner between crossbar and post.
Wellington pulled a goal back as Jason Hicks played Brockie through, only for Nikola Petkovic to give away a penalty, allowing Hernandez to slam home the penalty.
Just two minutes later Sydney were back to a twogoal lead as Ryall and Del Piero linked up well, allowing Ryall to slam home the goal to make it 3-1.
On the hour mark Sydney made it four as Ali Abbas was able to get some space on the edge of the area as he hit a volley from the edge of the area to make it 4-1 with an impressive strike.
Del Piero continued to look dangerous, especially from set-pieces which left Wellington, who were well out of the match, scrambling.
The win all but assures Sydney FC of the last finals place, with Newcastle needing a three goal win against Adelaide on Friday night and will need to rely on Sydney FC losing to Perth if they are going to advance to the finals.