The Swans went down to a 2-1 defeat at West Brom, but felt aggrieved not to have taken a point after Roland Lamah's late strike was wrongly ruled out for offside.
Michael Laudrup's side had taken a 33rd-minute lead when Luke Moore headed home Jonathan de Guzman's corner after the Swans had made a promising start.
But Romelu Lukaku levelled seven minutes later, steering home Graham Dorrans' low cross as the sides went into the break on level terms.
Referee Lee Mason then awarded the hosts a penalty after he adjudged Wayne Routledge to have fouled James Morrison. But Michel Vorm kept the Swans on level terms, diving low down to deny Lukaku's spot-kick.
West Brom did manage to take the lead, though, as Gareth McAuley headed home from a corner just past the hour.
Then came the controversial moment. Sub Roland Lamah tapped home from an acute angle after his initial cross deflected back to him via a Baggies defender and keeper Ben Foster, but the assistant referee's flag was wrongly raised.
That came with just two minutes left, and the Baggies held on to claim their first points against the Swans in the Barclays Premier League.
The Swans made two changes to the starting XI. With Leon Britton sidelined courtesy of a hip injury, Ki Sung-Yueng came into midfield alongside Jonathan de Guzman and top-scorer Michu.
Luke Moore, fresh from his late winner against Newcastle last time out, was recalled to the starting XI for the first time since Boxing Day as he turned out against his former club.
West Brom: Ben Foster, Billy Jones, Gareth McAuley, Jonas Olsson, Liam Ridgewell, Claudio Yacob, Youssouf Mulumbu, Graham Dorrans (Marc-Antoine Fortune, 88), James Morrison (Jerome Thomas, 88), Chris Brunt (capt), Romelu Lukaku (Peter Odemwingie, 81).
Subs: Boaz Myhill, Gabriel Tamas, Goran Popov, Markus Rosenberg.
Swans: Michel Vorm, Angel Rangel, Garry Monk (capt), Ashley Williams, Ben Davies, Ki Sung-Yueng, Jonathan de Guzman, Michu, Pablo Hernandez (Roland Lamah, 68), Wayne Routledge (Itay Shechter, 76), Luke Moore (Nathan Dyer, 61).
Subs: Gerhard Tremmel, Dwight Tiendalli, Kyle Bartley, Mark Gower.
The Jack Army were in fine voice at The Hawthorns, and they were close to cheering an opening goal after six minutes as Michu latched onto Pablo Hernandez's cross after a one-two, but the Swans' top-scorer couldn't keep his effort down.
The Swans kept applying the pressure as they continued their promising start, and Jonathan de Guzman's 20-yard free-kick whistled past the post as they signalled their intent.
Then a great counter attacking move involving de Guzman, Angel Rangel, Hernandez and Luke Moore set up Michu, but he stretched out and failed to keep his shot on target.
The home side first really tested the Swans as the game ticked past the half-hour mark as Romelu Lukaku's finely-judged pass sent Chris Brunt in on goal, but the Baggies skipper fired high and wide.
It proved costly as the Swans struck in the 33rd minute. From de Guzman's inswinging corner, Moore peeled off his marker Claudio Yacob and did fantastically well to direct his header past Ben Foster.
The lead would only last seven minutes, however, as Graham Dorrans' fine low cross found Lukaku, and the on-loan Chelsea striker steered past Michel Vorm.
Vorm then had to react quickly to keep out Brunt's thunderous effort as the Baggies finished the half strongly.
Half-time: West Brom 1 Swans 1
The first chance of the half fell to the hosts, with Lukaku volleying wide after Garry Monk had failed to deal with Liam Ridgewell's long ball down the left flank.
The striker then teed up Brunt, with Vorm having to collect between his legs to deny the midfielder.
Then referee Lee Mason made a big call, awarding West Brom a penalty after Wayne Routledge was adjudged to have fouled James Morrison.
But Vorm lived up to his Penalty Killer nickname, diving low to his right to deny Lukaku.
Michael Laudrup then made his first change, Nathan Dyer replacing scorer Moore which meant Michu moved up front with the Swans operating with three wingers.
The home side were ahead just seconds later though as Gareth McAuley rose highest to meet a corner, and his header appeared to already be over the line as Rangel's attempted clearance bounced back in off the back of de Guzman.
Roland Lamah and Itay Shechter were then introduced as the Swans looked for an equaliser in the last 15 minutes.
A Ben Davies cross was then tapped down by Dyer for Michu, but he failed to keep his volley down.
Then came a huge talking point as the Swans had the ball in the net for what they thought was a deserved equaliser.
Lamah beat his man down the right and when his low cross deflected back to him off a Baggies defender and Foster, Lamah tapped home from an acute angle with two minutes to spare.
But the celebrations were cut short as the assistant referee adjudged Lamah to have been offside after what he felt was a deflection off a Swans player.