The Hammers won 2-0 at the London Stadium to ease their relegation worries after Arnautovic returned from a three week injury layoff.
Speaking after the game, Hernandez said: "Marko is an unbelievable, all-around player and it gives you a lot of confidence when you play up front with a player like him. We have a good understanding with each other and both of us scored. That's a good thing for a striker."
Mexico's record goalscorer went on to praise the performance of his entire team, with the defence playing a key part in keeping a clean sheet.
"Not only did we score, but the whole team ran with high intensity and we showed that we wanted the three points," he added.
'Chicharito' has scored seven league goals this season since his move from Bayer Leverkusen and is enjoying a reprisal after considering leaving the London club in search of better first-team opportunties.