Sydney FC extended their unbeaten run in the A-League to 20 games with a 3-1 win over Wellington Phoenix on Thursday.

Having been held to a 0-0 draw by Brisbane Roar last time out, table-topping Sydney got back to winning ways in comfortable fashion and now hold a 12-point lead over Melbourne Victory.

Rhyan Grant opened the scoring inside three minutes as he headed Alex Brosque's left-wing cross beyond Wellington goalkeeper Glen Moss.

Grant then turned provider for Sydney's second in the 22nd minute, linking up intricately with Bobo, who turned home the return cross from the right-back for his eighth goal of the season.

Alex Rodriguez halved the deficit 10 minutes later as he flicked on a Gui Finkler corner at the near post.

But any hope of a Wellington fightback was put to bed nine minutes into the second half, Milos Ninkovic firing through the legs of moss having been picked out by Joshua Brilliante.

Defeat sees Wellington remain in eighth place, two points behind Western Sydney Wanderers in the last final series play-off spot.