By Mark Lamport-Stokes PACIFIC PALISADES, California (Reuters) - Rory McIlroy says he is excited about his Northern Trust Open debut this week at Riviera Country Club as he starts his tournament build-up in the United States for the Masters in April. While the opening major championship of the year will be firmly in his mind over the next two months, McIlroy has long desired to compete at Riviera, which is consistently ranked by the players as one of the top courses on the PGA Tour. "I wanted to come here because of what I had seen on TV, and the great things that people say about Riviera," world number three McIlroy, 26, told reporters on Wednesday after playing in the pre-tournament pro-am competition. More...