TOKYO, Oct 4 (Reuters) - Japan's Nikkei share average snapped a four-session losing streak on Thursday after Republican candidate Mitt Romney, who is seen as pro-business, appeared to come out on top over U.S. President Barack Obama in their first debate. "There is a certain school of people that have particular views on which candidate is better for the markets, specifically for the dollar ... It's probably an initial gut reaction to the presidential debate," a dealer at a European brokerage said. The Nikkei advanced 0.9 percent to 8,824.59, while U.S. S&P futures r ose 0 .4 percent. The broader Topix gained 1.1 percent to 735.38.