The 28-year-old forward says the draw felt like a defeat for the side that dominated most of the game
Tottenham star Son Heung-min says his team-mates are 'devastated' after they gave up a three-goal lead to draw 3-3 with West Ham.
Son opened the scoring for the home side in the first minute as he tucked into the bottom corner after taking on a pass from Harry Kane.
The England star then netted two of his own as Spurs were in full control after 16 minutes.
But West Ham fought back late in the second half, with Fabian Balbuena heading in the visitors' first goal before Davinson Sanchez knocked the ball into his own net and Manuel Lanzini secured a point with an incredible shot from distance.
Son admitted the Spurs players were in shock after the final whistle as they felt they should have won.
"The lads are devastated for the result, we think we deserved three points and played really well until the last 10 minutes. It's a shock," he told Sky Sports .
"It is football. It should never happen but it is part of football. We have to be focused until the referee's whistle. I don't want to feel this again, this is a good lesson for us to never happen again.
"We dominated the game from the start and scored three early goals and completely controlled the game. We had a couple more chances to score, but when you score three goals at home you can't drop points.
"It is so sad for me. The players, the team, are all sad. What happened, happened. It is just so sad. It should never happen again."
The 28-year-old told BBC Sport that the result felt worse than a draw and hopes they learn their lesson after letting their concentration drop.
"It hurt. I don't know what I should say... I am very sad, it feels like we lost the game," he added.
"The second half we still dominated the game and controlled the game, had a couple of chances we should do better. A football game is 95, 97 minutes, you have to be focused.
"We should remember this feeling forever so it never happens again. It is just so sad that we lost a big two points, when we as a collective played so well and as a team dominated and controlled the game, to draw the game feels like we lost."