The shot totals for both teams were dead even at 12 apiece, but the Tornadoes missed on some promising looks and probably felt they should have had more attempts given the number of chances.
Still, Hoover was a little more than a minute from ending a closely-played first half in a scoreless tie before Muir's Antonio Ceja drilled a shot into the middle of the net from 25 yards out.
"That goal changed the tempo, but I think our guys also have to be a little smarter," said Cadenas, whose team finished second in league last season, one spot above the Mustangs. "We're down, you've got to know not to make stupid fouls. A couple times it cost us. We had a couple chances to counter and our guys made stupid fouls in the back.
"But credit to Muir. Muir went out there and played aggressive. It was an aggressive game."
Hoover opened the second half, in which it took four shots on goal, with an aggressive sequence that saw Jesse Pina frame up two shots in the first four minutes that were saved, with the second coming on a breakaway.
In the 65th minute, Hoover's Teodik Zaghian was the recipient of a well-placed cross from Romel Sarkisloo practically on the goal line, but couldn't slip one past goalkeeper Miguel Magana, who finished with six saves for Muir (2-2).
Hoover also had several free kicks, including a pair from within 20 yards in the second half, and more than a couple instances when an opportunity appeared to open up only to be missed by dribbling rather than a timely pass or shot.
Cadenas said the Tornadoes will have to put this loss behind them quickly and be ready to face Arcadia at home when league play resumes at 3:15 p.m. on Friday.