Brazil's Copa America hopes hang in the balance after a disappointing 1-0 defeat to Colombia in Santiago on Wednesday night.
Dunga's men edged past Peru in unconvincing fashion on Sunday as Douglas Costa' late winner secured a 2-1 win, but there were no last-gasp heroics this time as Colombia notched an important win.
Jeison Murillo's first half goal handed Colombia all three points, with Brazil failing to clear a Juan Cuadrado cross before defender Murillo smashed the ball home.
Brazil were handed the perfect chance to equalise in the second half though, as in-demand forward Roberto Firmino was handed an open goal after a mix-up between Colombia goalkeeper David Ospina and defender Murillo - but he somehow contrived to put the ball over the crossbar.
The Hoffenheim star, 23, watched in horror as his shot sailed over the top - and Manchester United fans were far from impressed.
According to Brazilian newspaper Globo Esporte, United are pursuing a summer deal to sign Firmino after a great season in the Bundesliga, but may have to pay €25m to bring him to Old Trafford.
Fans took to Twitter after his shocking miss and disappointing display, suggesting that manager Louis van Gaal should instead play Brazilian compatriot Andreas Pereira instead, with the 19-year-old already making strides with the Red Devils.
Some fans urged supporters to be calm over Firmino and not to judge him on the basis of one game, but it's fair to say that most United fans were left unconvinced by Firmino's performance.
Here are some of the reactions from United fans on Twitter after Firmino's disappointing display against Colombia...
Firmino scouting report: He's just a poor man's Mata #MUFC— Stretfordenders (@20Manutdfc) June 18, 2015
United fans have never seen Firmino, but he misses one chance and he's not good enough. #mufc— Dario DB (@DarioChiller) June 18, 2015