The euro gained against the dollar for the first day in five as a technical indicator suggested its 3.9 percent drop in the past month was excessive. The U.S. currency yesterday strengthened to a nine-month high, pushing down the euro's 14-day relative strength index, a gauge of momentum over a given period, to 26.61, below the level of 30 which suggests the currency may change direction. ``The euro's slide was pretty fast and the currency looks really oversold,'' said Minoru Shioiri, head of currency trading in Tokyo at Mitsubishi Securities Co., a unit of Japan's second- biggest lender. ``It fell close to the key $1.20 level yesterday and we came to a point where we could see some upward correction in the short term.''