The Hammers became the first side in Premier League history to avoid defeat when trailing by three goals in the 81st minute, as Spurs imploded against their rivals.
Fabian Balbuena headed home a free-kick and Davinson Sanchez turned into his own net before Manuel Lanzini scored a stunning equaliser in the final minute of stoppage-time after the hosts had failed to clear another set-piece.
The draw left Spurs without a home win in the league this season and Mourinho said his players had to start capitalising on their positive performances having been 3-0 up inside 16 minutes.
Asked if the display on Sunday was 'Spursy' – a byword used by rivals supporters for bottling matches or falling just short – Mourinho said: "The nomination ['Spursy'] is not important for me. The past is not important for me. The future is of course important for me.
"What can I say, we are a team in evolution. I believe that nobody played better than us with the ball, which is a big evolution from last season. We are a very exciting team to watch I believe, and that is very important and that is the DNA we want to have. Is that enough to win football matches? No. You have the proof, that we only have eight points when we played so amazing in every match apart from the Everton match.
"But Southampton, Newcastle, Man Utd, West Ham, we played amazing football and this is very difficult to do but we are doing it. Of course, we need to play for a result and we have to learn how to do it.
"Against Southampton we were losing and we were strong enough to change the result.
"At Manchester United the worst thing happened, which was after one minute we were losing, and we were strong enough to change that result.
"Against Newcastle, we were solid, we weren't playing amazing, we were solid, and then what happened is one of the beauties of the VAR this season. So this game was completely out of context.
"I believe that winning 3-0 in minute 80 we could play 50 more matches and it's not going to happen again," Mourinho said. "So I don't want to be sticking on this and stories about 'Spursy', or this kind of thing.
"We have to just defend better at set pieces, because even defensively the team is playing very well. We conceded one single goal from open play against Southampton, one. Apart from that penalties, lateral free-kicks, VAR goals, and we are quite solid."
Mourinho is expected to rotate his side on Thursday but confirmed only that Sanchez would start again in the absence of injured pair Eric Dier and Japhet Tanganga.
Gareth Bale could make his first start since returning to the club against Austrian side LASK after coming off the bench at 3-0 on Sunday, while Carlos Vinicius is also pushing for a debut. Giovani Lo Celso and Erik Lamela are available after missing West Ham.
Bale showed a flash of his best on Sunday, weaving between two West Ham defenders before firing wide at 3-2, but Mourinho said he was a different player to the one who left the club in 2013.
"No player is the same with such a gap in time, 2013 to 2020 – we're talking about seven years, not speaking about seven months," the Portuguese said.
"It's not Gareth Bale, it's every player in the world.
"Seven years, the players they change. Sometimes it's not about changing for better or worse. It's about change. Just an evolution in their qualities, their style of play. Sometimes it's even in the positions they play. So of course it's not the same player, it's just a different player."