Leeds climbed to the top of the Championship with a battling 2-0 West Yorkshire derby victory over Huddersfield.
And victory was also Leeds' sixth win in a row and their seventh victory in nine games as they kept the pressure on the Baggies ahead of their home clash with Swansea on Sunday.
Town's defeat means they have not won in five matches despite a promising start when new manager Danny Cowley arrived earlier this season.
That meant opportunities for versatile Macedonian Alioski and Swiss defender Gaetano Berardi.
Cowley made three changes to his team following their 5-2 hammering at the hands of Bristol City last time out.
Town started brightly and created a good early chance. A quick free-kick from Juninho Bacuna caught the Leeds defence sleeping, but alert keeper Kiko Casilla made a smart point-blank block to thwart Mounie.
At the other end Mateusz Klich steered a right-foot shot against the right post from Hernandez's clever corner.
Centre-back Berardi made a superb block to get in the way of a Bacuna thunderbolt soon after, before Casilla produced a stunning one-handed save to deny Mounie.
The striker rose to head Bacuna's free-kick towards the top right corner, but an outstretched Casilla did brilliantly well to turn his header away.
Casilla was called into action again, this time saving Mounie's header from a Karlan Grant inswinging corner.
The Spanish keeper was so nearly to blame for gifting the hosts the lead just before the break, but captain Luke Ayling spared his blushes.
Casila raced off his line to clear Kamil Grabara's hopeful punt forward and the ball fell loose for Grant. Town's leading scorer saw his powerful left-foot shot superbly headed over his own crossbar by Ayling.
Leeds came out of the blocks firing on all cylinders after the restart and took the lead after only five minutes.
Alioski rifled into the bottom right corner to delight the visiting supporters behind the goal after Town failed to clear a corner.
Patrick Bamford headed wide and Hernandez rifled wide of the right post as Leeds pushed for a second.
Casilla denied Elias Kachunga an equaliser shortly after the hour mark with a wonderful close-range save from the midfielder's header.
Then Hernandez bagged a second Leeds goal to kill off the contest, heading home unmarked at the back post from Jack Harrison's inch-perfect cross.
Grant somehow headed wide from point-black range with nine minutes remaining and substitute Matty Daly dragged a shot inches wide of the right upright, but Leeds were worthy winners.