There could be an argument made for calling Clintons results a win. She did get more votes then Sanders even if those votes amounts are extremely close. It would be disingenous to just call something a tie when one person did in fact get more votes. A tie is when there is the exact same number.
Secretary Hillary Clinton is justified in calling her Iowa Caucus results a win; however, the results were a very marginal victory. Clinton's razor-thin win does not exactly inspire confidence in her leading position in the Democratic party, so it is a very small win in the overall Democratic primary race.
Hillary Clinton is not justified in calling her Iowa Caucus results a win because she essentially tied with Bernie Sanders. At the beginning of her campaign, she believed she would win the Democratic nomination by a landslide. Then Bernie Sanders came along and messed all that up. He is putting up a good fight in running against Clinton.
Iowa is only one poll in many and that doesn't mean that she won over Bernie Sanders just because she won at Iowa. They even mentioned that people weren't voting any more or less in Iowa, unlike a poll taken across the country, so I really wouldn't call it a victory just yet.