Hull head 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 Â£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.
"We tried to find solutions in the (transfer) market to help our team and Niasse was a player who was different to our other strikers," Silva said.
"He's one player to come here and help us. He feels as well that we believe in him and that's important for him and the other strikers."
Silva played a master-stroke by sending on Niasse for ineffective midfielder Alfred N'Diaye in the 63rd minute.
Niasse fired Hull ahead six minutes later after racing on to Abel Hernandez's first-time pass and slammed home his second from inside the area in the 78th minute.
"He knows, like the other players, sometimes you don't start a game," Silva said.
"But I know the right moment to change the course. Sometimes with all the changes it's nice, like today."
Silva was clearly relieved to have won a game he had described as "must-win" this week - Hull closed the gap on Swansea to three points - but was also left angry by the state of the KCOM Stadium's pitch.
Super League side Hull FC beat St Helens at the KCOM on Friday night and the Portuguese said he had told the club's owners the arrangement must be scrapped next season.
"I've said before, it's impossible at this level," Silva added.
"To play a rugby game yesterday on this pitch is impossible. There's so many things the club needs to improve.
"One team plays rugby on the Friday and then we play - for me it's impossible at this level. I've said this to our board. It's impossible. "
Swansea head coach Paul Clement said the first-half withdrawal of both Angel Rangel (foot) and leading goalscorer Fernando Llorente (dead leg) had been a major blow.
"The injuries hurt us," said Clement, who also revealed defender Martin Olsson had been forced to limp through the closing stages. "The fact you have to make two changes is never ideal.
"It's not down to who goes on and who comes off, it's more that in the second half a coach wants to have those options to be able to make changes.
"Having gone a goal down we made an offensive change and then our left-back also gets injured and you're playing with 10 and a half players. It did have an impact."
Clement was critical of his defenders for both Niasse's goals and bemoaned two glaring misses by Wayne Routledge in either half.
The winger fired against Hull goalkeeper Eldin Jakupovic's legs in the first half and blazed over the bar from seven yards in the second.
Clement also sympathised with Silva over the condition of the pitch.
"It's not ideal when you have a game the night before," he added.
"Any kind of game, never mind a rugby league game, the night before a Premier League game.
"In my opinion that's not right and I'm sure Marco Silva's not happy about that either."