Tottenham battled back to tie 2-2 with Manchester United despite knowing there must be no recurrence of their “unacceptable” St James’ Park disgrace, according to Heung-min.
Spurs’ dreams of finishing in the top four of the Premier League were dashed on Sunday by a 6-1 thrashing at Newcastle.
After that humiliating loss on Tyneside, interim manager Cristian Stellini was removed of his duties, and Ryan Mason assumed control of the team until the end of the season.
Tottenham looked to be in danger of suffering another mauling when they trailed the Red Devils 2-0 following goals from Jadon Sancho and Marcus Rashford.
But they rallied in the second half to salvage a point at Tottenham Hotspur Stadium on Thursday, Pedro Porro halving the deficit and Son equalising after being set up by Harry Kane.
Son said: “We wanted to give everything and that was the dressing room speech.
“We couldn’t let the game go. We were really angry about it, we didn’t deserve to be 2-0 down at half-time.
“The last week was unacceptable and we didn’t want to repeat that. We feel really, really sorry for the performance and result and we wanted to bring a good energy.
“We really appreciated [the fans’] support and they were fighting with us.”