The Cheetahs conceded a 78th-minute try to slump to a 27-26 loss to the Ospreys in Swansea on Saturday.
Considering the visitors had led until then, coach Rory Duncan will be incredibly disappointed with the result.
The Cheetahs produced all the early pressure and took an early 12-0 lead thanks to tries from hooker Torsten van Jaarsveld and lock Reniel Hugo.
Ospreys flyhalf Sam Davies reduced the deficit with a penalty, before Ospreys centre Ashley Beck, who would be named Man of the Match, crossed early in the second half.
The Cheetahs extended their lead through tries from centre Nico Lee and wing Craig Barry, but the Ospreys stayed in the contest as flank Sam Cross sprinted over to set up a tense finale.
The hosts continued to apply the pressure and were rewarded when replacement hooker Ifan Phillips dotted down and Davies added the conversion to snatch the win.
Ospreys – Tries: Ashley Beck, Sam Cross, Ifan Phillips. Conversions: Sam Davies (3). Penalties: Davies (2).
Cheetahs – Tries: Torsten van Jaarsveld, Reniel Hugo, Nico Lee, Craig Barry. Conversions: Neil Marais (3).
Ospreys – 15 Dan Evans, 14 Jeff Hassler, 13 Kieron Fonotia, 12 Ashley Beck, 11 Tom Habberfield (c), 10 Sam Davies, 9 Reuben Morgan-Williams 8 Sam Cross, 7 Guy Mercer, 6 Olly Cracknell, 5 James King, 4 Adam Beard, 3 Dmitri Arhip, 2 Sam Parry, 1 Nicky Smith.
Subs: 16 Ifan Phillips, 17 Rhodri Jones, 18 Ma’afu Fia, 19 Alex Jeffries, 20 James Hook, 21 Luke Price, 22 Owen Watkin, 23 Hanno Dirksen.
Cheetahs – 15 Clayton Blommetjies, 14 Craig Barry, 13 Francois Venter (c), 12 Nico Lee, 11 Malcolm Jaer, 10 Niel Marais, 9 Shaun Venter, 8 Uzair Cassiem, 7 Henco Venter, 6 Paul Schoeman, 5 Reniel Hugo, 4 Justin Basson, 3 Johan Coetzee, 2 Torsten van Jaarsveld, 1 Charles Marais.
Subs: 16 Jacques du Toit, 17 Ox Nche, 18 Erich de Jager, 19 Renier Bernardo, 20 Oupa Mohoje, 21 Zee Mkhabela, 22 Fred Zeilinga, 23 Luther Obi.
Photo: Huw Evans Picture Agency