Vedat Muriqi struck twice, with Dani Rodriguez also on the scoresheet for Mallorca, with Stefan Bajcetic scoring for the visitors.
Arrasate said afterwards: "It has been two difficult months, the victory frees us, the team has had fun at times and so have the fans.
"The 3-1 has put a bit of fear into our bodies because we have come from where we have come from and we have not been able to manage the changes as we wanted. With this victory we have taken a weight off our shoulders.
“I am satisfied with the ways we have found to create chances. We had chances to make it four, although we are struggling to keep a clean sheet.
"What I liked is the fluidity of the team and that with one goal down they went for the second and, with the second, for the third.”