The 19-year-old striker opened the scoring in United's 2-0 win over leaders Chelsea on Sunday as United extended their unbeaten Premier League run to 22 matches.
And the United boss believes the victory proves his team would have beaten Chelsea in last month's FA Cup quarter-final tie, had Herrera not received a controversial red card in that match at Stamford Bridge.
Chelsea failed to have a shot on target in an EPL game for the first time since September 2007, which also came against United at Old Trafford.
United moved up to fifth place, four points behind fourth-placed Manchester City with a game in hand, and is six points behind third-placed Liverpool having played two fewer games.
So, Spurs have the momentum, but Chelsea still has a four-point lead, which counts for a lot with only six games left.
With United still fighting in the Europa League, they remain outsiders to finish in the top four, but Darmian says Sunday's win has kept their hopes alive.
Sometimes, of course, we draw a lot of games at home".
"We stay in a great position, but Tottenham is in good form and playing very well and with enthusiasm".
Lyon goalkeeper Anthony Lopes was calmly walking off the field - after referee Amaury Delerue whistled the end of the first half - when he was confronted by a man. Lopes pushed him back as clashes erupted between home fans and Lyon players.
Marcus Rashford can be one of the world's best players, according to Manchester United teammate Matteo Darmian.
United wwasahead on seven minutes after Herrera had split the Chelsea ddefensewith a flawless pass to Rashford, who swept home past Asmir Begovic.
Chelsea coach Antonio Conte was under no illusions as to how important each of those games will be.
"On the counter-attack we hurt them but we played football as well; we controlled the game".
"In this case I wasn't able to transfer the right motivation to play this type of game".
"We have felt that kind of performance coming", the versatile 31-year-old added. I think Arsenal here [a 1-1 draw], Tottenham [Hotspur] here [a 1-0 win], we played really well but today I think was a special performance because it was a special opponent: the leader, the way they play, and I think we played really well, very solid performance.