Working his socks off for 70 taxing minutes before being replaced by Stefan Kießling, the 27-year-old striker became the fourth Mexican to score in the Bundesliga as die Werkself drew a much-needed line under an unforeseen three-match losing run.
'We believe in ourselves'
"We fought a lot," Hernandez told bundesliga.com after the game. "After the disappointment of losing to Dortmund, we won. The goal helped us a lot to control the game and get the points."
To their credit, Leverkusen have not allowed their heads to drop following disappointing defeats to FC Bayern München, SV Darmstadt 98 and Borussia Dortmund. They had not scored in any of those games, yet remained firm in their convictions against a Mainz side in top form.
"Pressure's part of the game, but we believe in our squad, we believe in ourselves, in the way we like to play," Hernandez continued. "We just need to try to prove it because there's no team that's going to be excellent from start to finish."
'We played as we wanted to'
Considering Leverkusen have lost three of their six Bundesliga assignments so far in 2015/16, the fact they are only two points behind fourth-placed VfL Wolfsburg should offer great encouragement to a squad of players, in some ways, still feeling each other out.
The likes of Jonathan Tah, Andre Ramalho, Christoph Kramer (loan return), Admir Mehmedi and, of course, Hernandez, are all relatively fresh on the books at Bayer 04, but there are already signs that the new boys are beginning to click.
"We need to get used to the new players," Leverkusen's 'Little Pea' acknowledged. "Some players left too. We need to keep working, but the most important thing is that we played as we wanted to. We didn't concede or give away many chances. We created a chance and scored […] I'm happy."