Defender Damion Lowe gave the Reggae Boyz a 13th minute lead, which was later cancelled out by substitute Brandon Vazquez in the 88th minute to rescue a point for United States in a contest that lived up to its billing in entertainment value for the massive crowd at the Soldier Field in Chicago.
Though they will be pleased with the point, the Jamaicans will also feel hard done given the fact that Leon Bailey should have converted from the 12-yard spot. But take nothing away from United States goalkeeper Matt Turner, whose save on his birthday proved the difference, though Reggae Boyz captain Andre Blake was also at his best between the sticks to spare their blushes.
Both teams started positively and signalled intentions with a few direct passes from the back into the attacking third to keep their respective defensive units on their toes.
Jamaica found a break in the eighth minute with Bailey finding debutant Demarai Gray out wide, the Everton winger showed glimpses of his nippy footwork and later played a dangerous pass inside that was cleared by the United States defence.
The host responded almost immediately and caught Jamaica's defenders flat-footed with Jordan Morris finding loads of space in the final third to get a shot off from close range that was kept out by Blake who got down well to his left.
Still, United States struggled to deal with the pressure posed by the new look Reggae Boyz as again set pieces proved their undoing when the Jamaicans eventually broke the deadlock.
After Bailey was fouled by Jordan Morris, Gray delivered a perfectly weighted free kick which was expertly met by Lowe with a diving header that gave Turner in goal for United States, no chance at a save.
Jamaica should have doubled the lead from the penalty spot just before the half-hour mark when Amari’i Bell’s long throw inside the danger area was headed on by Michail Antonio to Kevon Lambert, who was taken out by Aidan Morris’s high boot.
Mexican referee Cesar Ramos quickly pointed to the spot and Bailey confidently stood over the ball, but the Aston Villa winger badly fluffed his lines, sending his penalty at a perfect height for Turner to save. He had a grand opportunity to make amends but steered the rebound wide as well.
That missed opportunity gave United States hope and they gradually found their rhythm, though they were assisted by some sloppy Reggae Boyz defending at times. One such occasion was in the latter stages of the first half, when Jordan Morris easily waltzed his way through on goal and it took some brilliance from Blake to deny him.
With momentum in their favour, United States came out lively on the resumption as Head coach BJ Callaghan made the adjustments with the introduction of Vazquez, Cristian Roldan and Djordje Mihailovic, who injected some tempo into their attacking thrust, as they probed for the equalizer.
A gorgeous interplay by United States in the 70th minute paved the way for Roldan to get a shot off from close range, but Blake again came up big to keep the Reggae Boyz in front.
As the game drew closer to its climax, the Jamaicans withdrew into a defensive posture, desperately trying to preserve their lead which would have not only handed Hallgrimsson his first win eight games, but also condemned United States to their first Gold Cup opening loss.
The victory would have also been Jamaica’s second against United States at this tournament following their semi-finals triumph in 2015.
However, all that went out the window when Vazquez pounced on a poor clearance from a Jesus Ferreira cross to put the ball away from close range.
This stalemate represents an opportunity for Trinidad and Tobago or St Kitts and Nevis to assume early pole position in the group, provided they separate themselves in Sunday’s fixture.
Teams: Jamaica -Andre Blake, Dexter Lembikisa, Damion Lowe, Adrian Mariappa, Amari’i Bell (Kemar Lawrence 65th), Bobby Reid, Joel Latibeaudiere, Kevon Lambert, Demarai Gray (Daniel Johnson 90th), Leon Bailey (Shamar Nicholson 90th), Michail Antonio (Corey Burke 75th)
Subs not used: Coniah Boyce-Clarke, Jahmali Waite, Dishon Bernard, Javain Brown, Kaheem Parris, Jonathan Russell, Dujuan Richards
Booked: Lowe (3rd), Lawrence (83rd), Blake (85th)
United States: Matthew Turner, Deandre Yedlin, Matt Miazga, Aaron Long (Jalen Neal 46th), John Tolkin (Brandon Vázquez 82nd), Alejandro Zendejas (Djordje Mihailovic 66th), Aidan Morris, James Sands, Jordan Morris (Cade Cowell 55th), Jesús Ferreira, Alan Soñora (Cristian Roldan 66th)
Subs not Used: Sean Johnson, Gabriel Slonina, Bryan Reynolds, Miles Robinson, Dejuan Jones, Gianluca Busio
Booked: None
Referee: Cesar Ramos (Mex)
Assistant referees: Alberto Morin (Mex); Marco Bisguerra (Mex)
Fourth Official: Fernando Guerrero (Mex)
Var: Erick Miranda (Mex)
Avar1: Jorge Perez (Mex)