Toronto FC coach John Herdman and Nick Cushing, his New York City FC counterpart, stood their ground Monday over allegations that a 19-year-old Toronto player had been punched in the face in the Yankee Stadium tunnel at halftime of a March 16 game.

Herdman said he believed his player. Cushing repeated the denial he made Saturday night when apprised of the Toronto accusation.

"I categorically deny any involvement or any incident where I have punched or assaulted any Toronto FC player or staff member," Cushing said in a statement before a media availability Monday.

"I am shocked personally and upset by the allegation," he added. "We as a club have proactively asked MLS to investigate the incident on Saturday evening. And I will leave it with MLS and our legal team to carry out the investigation."

The allegation came Saturday night after the two teams clashed on the pitch following NYCFC's 3-2 win at BMO Field. Following the match, Herdman and captain Jonathan Osorio said the bad blood stemmed from New York's 2-1 win at Yankee Stadium in March, saying one of TFC's young players had been cornered at halftime of that game.

"The 19-year old reported being punched by the coach in that stadium," Herdman said Saturday.

He did not identify the player assaulted but the age fits Jahkeele Marshall-Rutty, who opened the scoring in the March 16 game.

Apprised of Cushing's denial, Herdman held firm Monday.

"The honest information that was relayed back from the team and the young player was that there'd been that altercation. As a coach, I've got to believe my players and support and back my players," he said.

Major League Soccer said its disciplinary committee was looking into the Saturday night clash and was aware of the accusations that followed.

With Toronto and Philadelphia both playing Wednesday — at Nashville and Philadelphia, respectively — any supplemental discipline is likely to come sooner than later.

Trailing 2-0 at the half Saturday, Toronto mounted a comeback and cut the New York lead to 3-2 with a 89th-minute goal. TFC pressed unsuccessfully for an equalizer during seven minutes of stoppage time that stretched to nine minutes because of NYCFC injuries/time wasting.

Irate that referee Lukasz Szpala had not added more minutes, Toronto wingback/winger Federico Bernardeschi rushed to confront him after the whistle and was shown a second yellow card.

As Cushing left the field, Herdman approached at speed and bumped his counterpart, clearly with something to say. A member of the NYCFC staff pushed Herdman away but emotions continued to rise.

"I was just disappointed that it had kicked off again," Herdman said Monday by way of explanation.

"We finished the game, we were trying to do our thing in our own half and I felt their players were in our half of the field. They didn't need to be," he added. "I think given what had happened in the previous game, you take your three points, you shake the referee's hand and you get to your dressing room.

"I just felt it was unnecessary what was going on and he seemed to be at the front of it again."

Cushing said he went on the field after the game to shake the referee's hand "and turned around and there was a big melee."

Herdman pointed to halftime of the March 16 game, saying Cushing "had been in the midst of everything" as the team left the field.

"I did see the footage in the tunnel of him inciting my players — unnecessarily. Our players are just walking to their dressing room so I got to see some of that behaviour."

TV footage showed Toronto midfielder Deybi Flores exchanging words with the New York coach.

Toronto goalkeeper Sean Johnson and NYCFC's Strahinja Tanasijević were in the middle of Satruday's melee, with an irate Johnson trying to get at the Serbian defender. Osorio said later that his goalkeeper had been head-butted.

Johnson was joined by Osorio, Flores and Toronto teammates Prince Owusu, Matty Longstaff and Kosi Thompson in the middle of the melee.

Owusu eventually went down and was swallowed up by the rolling ball of humanity which numbered some 30 people by the time it reached the sideline with Johnson eventually grabbing Tanasijević in a bear hug.

Toronto assistant coach Jason deVos had to restrain Flores, who clearly wanted a piece of someone.

Herdman said his club had requested video footage from NYCFC from the March game. The footage received did not show the alleged incident, although Herdman said it showed "evidence of other things that were going on."

"In terms of any footage of a 19-year-old being physically accosted, there was no footage of that," he added. "Apparently the cameras weren't working or didn't cover that part of the facility (where) that alleged incident happened."

The footage was also reviewed by the league, he said.