That handed the Hornets a first point after three successive defeats, but represented a disappointment for Steve Bruce's Newcastle, which had gone into the game with high hopes of building on last weekend's 1-0 win at Tottenham.
Bruce had suggested before the game that six points from the first four fixtures would represent a satisfactory start to the season, but the task of collecting the three required to reach that total became significantly more difficult within two minutes of kickoff.
Tom Cleverley picked up possession 30 yards (meters) out and was allowed to advance before unleashing a shot which ricocheted off both Paul Dummett and Jamaal Lascelles and fell into the path of the unmarked Hughes, who calmly side-footed past goalkeeper Martin Dubravka.
Newcastle was level four minutes before the break when the ball fell to Schar after Isaac Hayden had challenged Craig Dawson for Emil Krafth's cross, and he fired into the far corner.
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