Atlanta United were crushed by Monterrey in their CONCACAF Champions League quarter-final first leg to continue Frank de Boer's tough start at the helm.

The MLS Cup champions suffered a 3-0 loss to Monterrey in their opening leg in Guadalupe on Wednesday.

De Boer, who replaced Gerardo Martino at Atlanta late last year, has now lost three of his first four competitive games in charge.

It appeared the MLS side would not be in an overly bad position heading into the return leg, despite falling behind in the 17th minute.

Nicolas Sanchez opened the scoring from the penalty spot, but Monterrey needed until the final 10 minutes to take control of the tie.

Dorlan Pabon made it 2-0 with a 20-yard strike before Jesus Gallardo drilled in from close range as the Liga MX outfit recorded a comprehensive win.

It leaves Atlanta needing another turnaround – they overturned a 3-1 first-leg deficit against Herediano in the last 16 – in the second leg on March 13.

In Panama, Independiente grabbed a 2-1 win over Sporting Kansas City in their first leg.

Ivey Romeesh's opener for the hosts was cancelled out by an Ilie penalty, but Independiente found a winner just before the hour-mark through substitute Alexis Corpas' stunning effort.