Rayo Vallecano started the game with a lot of confidence after their best start to a season since 2012/13, but that confidence soon took a massive hit 13 minutes in as Dani Rodriguez stole the ball with the centre-backs sloppily playing a long pass across the backline.
The Spaniard ran into the box and chipped over the recovering defenders to find Muriqi at the back post, who headed back across goal for the opener.
Not discharged by conceding their first goal of the season, Los Franjirrojos regrouped in search of an equaliser.
They nearly had it around the half-hour mark, as Oscar Trejo caught the ball just outside the box and curled an effort on goal that deflected onto the post, leaving Predrag Rajkovic flat-footed and thankful for his teammate's intervention.
That effort was the hosts’ best chance as they went into the interval behind, having struggled to break down Mallorca’s back five.
The second half started as the first ended with Rayo continuing to press for a goal, but Mallorca continued to stifle the hosts and even began to create the better chances as they frustrated the opposition.
Finally, one of those few chances paid off when Rajkovic smashed a long ball upfield, before it was weakly nodded towards goal by a Rayo defender, and picked up by the advancing Lee.
The South Korean went one-on-one with Stole Dimitrievski and shot low at the near post to make it 2-0.
For Los Piratas it was a much-needed win to kick-start their LaLiga campaign and build some momentum.
Meanwhile, Rayo will be frustrated not just by the defeat but the manner of how they conceded both goals when they had general control of the game for most of the proceedings.
Flashscore Man of the Match: Lee Kang-in (Mallorca)
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