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Celtic defender Johan Mjallby tracks the run of Boavista forward Duda during a dull first half

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Midfielder Stillian Petrov looks to support the Celtic strikers but there is little threat of a goal before the break

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Celtic skipper Paul Lambert tries to drive his side forward as they search for the breakthrough at a packed Celtic Park

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Bhoys boss Martin O'Neill urges his side forward but Boavista stubbornly resist the Scottish champions

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Joos Valgaeren scores an own goal in the 49th minute but Celtic striker Henrik Larsson equalises less than a minute later

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Larsson goes from hero to villain in the 74th minute when his penalty is saved by Boavista's goalkeeper

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With just seconds remaining, John Hartson heads wide from a corner and Celtic have to settle for a draw