DOHA: Al Arabi on Sunday beat Al Wakrah 4-0 to reach the quarter-finals of the Emir Cup.   Kwame Karikari (7) opened the scoring for Al Arabi who saw their lead doubled when Hamad Mohsen Al Harbi found the net in the 26th minute with a powerful shot from close range.   Brazilian Diego Gardel added Al Arabi's third goal in 40th minute at Grand Hamad Stadium as the Doha giants looked at ease in the match.   In injury time, Al Arabi scored their fourth goal when Karkari found the net with a late strike.   Both teams for most parts of the second half attacked frequently but none of the sides could score until the 91st minute in the match.   The Emir Cup quarter-finals will be played on May 3 and 4.   The final of the country's most popular event will be played at the Khalifa International Stadium on May 19.