Arsenal coach Mikel Arteta said their first victory over champion Manchester City in eight years on Sunday sends a message to his team that it must believe and trust. The Gunners had not enjoyed a league victory over City in 15 matches, having lost the previous 12 in a row before Sunday’s clash at the Emirates between last season’s title rivals. After a closely fought match, substitute Gabriel Martinelli struck late on to secure a 1-0 win and send the Emirates into delirium as the Gunners moved level on 20 points with league leaders and fierce rivals Tottenham Hotspur.