Perth Glory goalkeeper Liam Reddy almost single-handedly denied Sydney before the champions prevailed in a match twice impacted by storms.
A lone second-half Kosta Barbarouses strike was enough for Sydney to secure a narrow 1-0 win against Perth Glory and climb to fourth in the A-League.
The match ended in unusual circumstances with some of the lights going out at Jubilee Stadium on Wednesday and lightning nearby.
Under A-League rules, the result stood despite the match ending a minute before fulltime with a further four minutes of added time still to be played.
Barbarouses secured the winner nine minutes after half-time, Glory now having failed to score in seven away matches against Sydney.
The match was played on a greasy surface after the start was delayed by 45 minutes as a lightning storm swept across southern Sydney before kick-off.
The Sky Blues created countless goalscoring opportunities but Glory goalkeeper Liam Reddy made several inspired blocks.
It was shaping as yet another night of misfortune in front of goal for Sydney with the reigning champions struggling to breach Reddy's defences.
Despite Reddy's form, the veteran shotstopper should have kept out Barbarouses's match-winning strike with the low angled shot bursting through his hands.
Sydney's attacking stocks were boosted for the contest with Alex Baumjohann coming in to replace the rested Calem Nieuwenhof.
Perth were equally buoyed by the well-timed return of Andy Keogh after Diego Castro had been ruled out for a month on match eve.
Glory coach Richard Garcia surprisingly left midfield engine Neil Kilkenny on the bench with the regular skipper not entering the fray until the final 10 minutes.
The Sky Blues could have been out of sight at the break with striker Bobo twice denied, firstly by a close-range block which ricocheted onto the crossbar and then by a one-handed save.
Attacking midfielder Milos Ninkovic, who created numerous openings, had his own clear first-half opening but again Reddy was up to the challenge.
Perth enjoyed their positive moments in attack, notably wide-player Carlo Armiento was a constant source of concern for the home side.
Perth Glory always looked capable of undoing their opponents on the counter-attack through Bruno Fornaroli, Keogh and Armiento.
The Sky Blues survived a nervy final few minutes to move five points adrift of top spot with a match in hand, while Glory remain in ninth.