Meireles arrived from Liverpool last week.
"We have a good three months to focus on the real objectives," Villas-Boas says.
"Signing Raul Meireles was an extremely good deal for us and we are happy to have him here.
"I had said we needed one more player in midfield. Yossi Benayoun had variability, he could play in the middle and he could play out in the channels or behind the striker, but we felt that towards what we wanted to achieve in terms of playing style, Raul would fit with this requirement."