Hermoso, 33, came on as a second-half substitute for world champions Spain in their 1-0 Nations League win over Italy in Salerno, after not being selected for games in September by coach Montse Tome to "protect" her.
She questioned Tome's decision at the time and was subsequently called up last week for the trip to Italy and a visit to face Switzerland on Tuesday. Hermoso, who now plays for Pachuca in Mexico, replaced her former Barcelona team-mate Mariona Caldentey after 67 minutes with the game goalless.
The attacking midfielder was in the right place at the right time to fire home the rebound after Alexia Putellas' shot was saved in the 89th minute, celebrating jubilantly.
Hermoso was later booked for blocking a quick free-kick by Italy as she helped Spain hold on for the victory, which helps them hold on to top spot in League A Group 4.
"I can tell you (I thought about) many things, but life sometimes gives you little gifts, and today I thought about a lot of people behind (me) this time," Hermoso told TVE. "I am happy because thanks to them today I enjoyed football once again."
Hermoso is Spain's top goalscorer with 52 goals for her country in 102 appearances. "What better joy than to get back here and feel good again, to score the goal that gets the win -- now I can only smile," she added.
Hermoso became a symbol in the fight against sexism and earned global support after Rubiales forcibly kissed her on the lips following Spain's triumph over England in Sydney on August 20, although he says it was consensual.
Rubiales resigned three weeks after the kiss after widespread criticism and has been charged with "sexual assault" by a Spanish court and banned from coming within 200 metres of the player.
Spain's World Cup winning coach Jorge Vilda was sacked by the Spanish federation in the wake of the scandal at a time dozens of Spain players including Hermoso were on strike, demanding profound changes. La Roja are aiming to qualify for the 2024 Olympics by reaching the Nations League final.