Thompson, who joined Sydney just before the start of the season as cover for the injured Peter Triantis, will now take the place of Rhyan Grant who is out for the season with a knee injury. 

The 31-year-old has done an admirable job for the Sky Blues so far this campaign, playing in 10 of the 13 games to help Frank Farina's side sit comfortably in the top six. 

"I've really enjoyed my time at Sydney FC so far and I'm delighted to be staying on until the end of the season," Thompson said. 

"Training has been very intense recently with a lot of competition for places, so I'm happy I have been able to show the coaches what I'm capable of both on the training field and in the games.

"Hopefully I can put in some more good performances between now and the end of the season and help the team qualify for the finals." 

With Nick Carle (suspended) and Hagi Gligor (Australia under-22 duty) unavailable for Saturday night's massive derby against the Western Sydney Wanderers, Thompson is in line for a return to the starting side for the Pirtek Stadium clash. 

"Matt has done well since he has come to the club and has impressed us with his attitude and work rate," Farina said. 

"I hope we will continue to see more from him as the season progresses and we prepare for the finals series."