The game started off perfectly for the hosts, who took the lead just 1 minute 26 seconds after kickoff. Dorlan Pabón put the Rayados in front with a shot from outside the box into the upper corner, putting Santos Laguna in an immediate hole.
The early goal inspired Monterrey, and they kept the pressure on. It wasn’t long before they were on the board again; in the 7th minute, Nicolás Sánchez headed home a corner kick to make it 2-0 for the hosts.
Then, in the 12th minute, it looked like they had made it 3-0 when Vincent Janssen played Carlos Rodríguez in behind the defense, where he went one-on-one with Jonathan Orozco before burying the ball in the back of the net. However, after VAR review, the would-be goal was disallowed for a handball on Janssen in the build-up.
That call seemed to change the momentum of the game, especially after Santos Laguna reduced the deficit in the 22nd minute. Julio César Furch got the visitors back into the game as he drove down the center and sent a low shot past Marcelo Barovero from just inside the box to make it 2-1.
Then, in first-half stoppage time, Monterrey was unable to clear away a corner kick and after some ping-pong in the box, Eryc Castillo stooped to put the ball away with a diving header and make it 2-2.
Monterrey reclaimed the lead soon after the second half began, though. In the 51st minute, the unfortunate Gerardo Arteaga was credited with an own-goal after Dorlan Pabón sent the ball in and Brian Lozano’s attempted clearance went straight into his teammate and in to make it 3-2 for Monterrey.
Then, in the 67th minute, the Rayados won a penalty kick after Ulises Rivera was called for a foul on César Montes in the box. Nicolás Sánchez, Monterrey’s official penalty taker, ceded the ball to Janssen, who converted the spot kick to make it 4-2.
The final goal came in the 84th minute. With Santos throwing numbers forward for a set piece, Monterrey struck on the counter through Dorlan Pabón, whose shot from outside the box made it 5-2.
With the 5-2 win, Monterrey will advance with a win, a draw, or a one- or two-goal loss in Sunday’s second leg. They can advance with a three-goal loss as well, so long as they score at least three themselves. Santos Laguna needs to win by at least three goals to move on; 3-0 or 4-1 would do it thanks to away goals, and 5-2 would put them through as the higher seed.