(Was only watching with half an eye, thought the blue player was the attacker and agreed with the referee. Then I saw the blue player was the defender...)
Defender had advantage, guess he just wanted to defend his position and prepared for a shoulder charge to hold off the attacker (so the goalkeeper could collect the ball). First contact is the attacker kind of pulling back the defender's arm, defender gets unbalanced, shoulder charge gone wrong. Although defender seems to look for extra contact (under the disguise of being unbalanced) as he tries to prevent the atacker from reaching the bal. Attacker kind of loses his footing, not doing all he can to stay on his feet, but there's serious contact, wouldn't call it a dive.
I would say play on.