Complex sentence: His first official competition was the AFF Suzuki Cup 2014, in which he led the team through the group stage and defeated Malaysia 2-1 in the first leg of the semi-final round in Malaysia.
Split into simpler sentences: His first official competition was the AFF Suzuki Cup 2014. In which, he led the team through group stage and defeated Malaysia 2-1 in the first leg of the semi-final round in Malaysia.