Al Qadsia, who lost to domestic rivals Al Kuwait in last season's final, were on course for a first-leg victory when Bader Al Mutawa struck early at the Al-Sadaqua Walsalam Stadium on Tuesday.
Al Mutawa put the Kuwaiti champions ahead after just five minutes with his second goal in as many AFC Cup games this season.
However, Al Khaldi snatched what could prove to be a vital away goal two minutes into the second half to ensure the match finished 1-1.
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Al Qadsia, who have won three domestic trophies this year and beat Al Hadd 2-0 at home in the group stages of the 2014 AFC Cup, were widely expected to have too much for their Bahraini visitors - who had not played a competitive fixture since May.
But Al Hadd showed superb resolve to earn a draw, and will take heart from the fact they defeated Al Qadsia 3-2 at the Bahrain National Stadium back in April.
A repeat of that scoreline in next week's second leg would be enough to take them to the semi-finals.
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