The 10th-minute dismissal of defender Ximo for a professional foul left Mallorca up against it at the Coliseum Alfonso Perez and hosts Getafe took full advantage to record only their second win of the campaign.
Diego Castro struck the winner in the 49th minute as Getafe rocketed up to 11th place, while Mallorca, who would have joined third-placed Malaga on 14 points with a victory, slipped down a spot to fifth.
In-form Mallorca, in buoyant mood following their victory over Valencia last time out, soon tested their former goalkeeper Miguel Moya, although the Getafe custodian had little trouble dealing with Tomer Hemed's early strike.
The next significant incident was the one that ultimately shaped the match, with Ximo shown a straight red card after a foul in Getafe winger Castro.
The home side soon looked to make the most of their numerical superiority and Abdelaziz Barrada drew a fine save out of Dudu Aouate in the 26th minute.
The visitors managed to hold out until half-time, but their backline was breached just four minutes after the restart as Castro turned in Pedro Leon's ball into the box, and that proved to be the match-winner.
Mallorca came close to an equaliser in the 59th minute with a Anderson Conceicao header that Moya did well to tip over, while Jose Carlos Nunes and Pedro Geromel both shot wide for the visitors in the closing stages.
However, they could not find an equaliser as Getafe, who had chances of their own to claim a more comfortable win, took the spoils.