Cristiano Ronaldo returned to his ruthless best, firing home a hat-trick as Real Madrid thrashed Real Sociedad 5-2 on Saturday in La Liga to warm up for their Champions League clash with Paris St Germain in style.

Lucas Vazquez broke the deadlock for Real after 49 seconds and Ronaldo added the second after superb work by Marco Asensio and Marcelo.

Toni Kroos curled home the third from outside the area and Ronaldo headed home Luka Modric's corner for the fourth in the 37th minute.

The Portuguese forward completed his treble after Geronimo Rulli beat away Gareth Bale's long-range effort late on, with Jon Bautista and Asier Illaramendi pulling goals back for Real Sociedad.

Madrid moved third in La Liga but trail leaders Barcelona by 16 points as they turn their attention to the defence of their Champions League title when PSG arrive at the Santiago Bernabeu on Wednesday.