The win, with all the goals coming in the second half, means Mexico lead Group B with six points from two games, with Haiti three points behind.
Qatar and Honduras both have a point each, drawing 1-1 earlier on Thursday after a stoppage-time leveller from the Central Americans.
Mexico dominated the opening 45 minutes but were unable to find a way past Haiti keeper Alexandre Pierre.
Pierre almost gifted El Tri an opener in the fourth minute when he fumbled a low cross but Edson Alvarez, with the goal at his mercy, struck the post.
Haiti came close when a counter-attack down the right ended with Carlens Arcus finding an opening but his shot, from a promising position, flashed into the side-netting.
Mexico wasted another opportunity three minutes before the break when a defensive slip-up left Henry Martin unmarked but his shot was poor, straight at Pierre.
Whatever Mexico interim boss Jaime Lozano said at half-time delivered instant results, however, with Henry Martin finding the target just 41 seconds after the restart.
A Ricardo Ade own goal made it 2-0, after the Haiti defender's attempt to intercept a low cross from Jesus Gallardo ended up in his own net.
But Haiti remained determined and gave themselves a lifeline with a 78th-minute header from Danley Jean Jacques from a Derrick Etienne Jr corner.
With the Caribbean side pushing forward, Mexico exploited the space to settle the game -- Uriel Antuna's great low ball across the area turned in at the back post by a full-stretch Santiago Gimenez.
Guest team Qatar took the lead against Honduras in the eighth minute when Tameem Mansour rose to head home an excellent cross from Mostafa Meshaal.
Honduras struggled to create clear chances but Jose Pinto went close in the 87th minute when he cut in from the left but his sweet right-foot shot was superbly saved by Meshaal Barsham.
But in the sixth and final minute of stoppage time, a Pinto deep ball into the box was headed down by Rubilio Castillo and Alberth Elis hooked in the equalizer.
Friday's matches in Group C, in Houston, pit Martinique against Panama and Guatemala against Canada.
