Muramatsu qualified for his third PDC World Championship, and second in succession, in 2013 by winning the Japan Qualifying Event. He played Dave Harrington of New Zealand in the preliminary round, winning 4–0 to set up a first round match against Simon Whitlock which he lost 3–0. He played in his third World Cup of Darts and first with Sho Katsumi in February and they advanced from Group A thanks to a 5–4 win over Austria. They then defeated the Republic of Ireland 5–3 to face the top seeds of Phil Taylor and Adrian Lewis in the quarter-finals. Muramatsu lost to Taylor 4–1, but Katsumi defeated Lewis meaning that a doubles match was required to settle the tie. Japan led 2–0 but went on to lose 4–2. He was edged out 6–5 by Hashimoto in the final of the Japanese qualifier for the 2014 World Championship.