Hull coach Marco Silva said he had always believed in match-winner Oumar Niasse after the substitute's two goals secured his side a 2-1 win against relegation rivals Swansea.
Niasse had failed to deliver at parent club Everton after arriving from Lokomotiv Moscow in a £13.5million deal in February 2016, but was drafted in on loan by Silva in January and his two second-half goals sealed three crucial points in the Tigers' bid for survival.
Swansea defender Alfie Mawson headed home in stoppage time to ensure an anxious finale, but Hull held on to climb to within one point of safety.