TOKYO, Feb 4 (Reuters) - Japan's Nikkei stock average fell 4.2 percent to a four-month low on Tuesday, as the yen's rise hurt sentiment after weaker-than-expected American factory data created worries about the U.S. economy. The benchmark Nikkei, extending its losing streak to a fourth day, ended 610.66 points lower at 14,008.47, the lowest closing since Oct. 8. It was the biggest one-day percentage decline since June 2013. The Nikkei fell decisively below its 200-day moving average, around 14,425, for the first time since November 2012 when the market started rallying on expectations of radical monetary easing. The broader Topix index tumbled 4.8 percent to 1,139.27, with 4.233 billion shares changing hands, the highest since June 2013. The JPX-Nikkei Index 400, an index launched this year comprised of firms with high return on equity and strong corporate governance, shed 4.7 percent to 10,330.02.