The Hungarian, who has been absent since rupturing knee ligaments against
Tottenham in December, was a 71st-minute substitute at Parken Stadion.
The Baggies led 1-0 at that point thanks to Steven Reid's 15th-minute goal.
And two late strikes gave the scoreline an emphatic look, with Shane Long
winning and converting an 89th-minute penalty and Gabriel Tamas netting the
third in stoppage time.
Goalscorer Reid wrote on Twitter afterwards: "Nice to get a 90 (minutes) under the belt and a good 3 nil win! Good end 2 a great trip!''