Extending its gains for the third straight day, the Sensex at the Bombay Stock Exchange climbed 63 points, or 0.3 percent, to close at a fresh two-year high of 20,102, today, amid some strong corporate results, and positive European markets. The Nifty at the National Stock Exchange rose 18 points, or 0.3 percent, to 6,082.Stock markets in Japan, China, Hong Kong, South Korea and Singapore ended mixed.