The Liga champions went through to the last 16 of the Copa del Rey regardless thanks to their 3-0 triumph in the first leg, but L'Hospitalet pulled off a shock as they twice pegged the hosts back in the return encounter.
In front of a sparse crowd at the Vicente Calderon, Mario Mandzukic put Atletico ahead twice, but Ruben Alcaraz netted a brace of his own to seal an unlikely draw for the Segunda B3 side.
Alcaraz netted his spectacular second, a fierce drive from 35 yards, with six minutes to go and, although Atletico failed to meet expectations with a dominant win, Simeone was not displeased.
"In this year  we only lost a game at home in the Calderon," the Argentinian told reporters.
"That speaks volumes of the work of our players. Hopefully we can continue in the same way.
"With regards to the match, I'm happy. We started the match well and score, but in the second half the boys of L'Hospitalet reacted well. They had some luck with the first goal and the second was a great goal."