Manchester United boss, Erik ten Hag, has singled out winger Alejandro Garnacho for praise following his side’s Premier League 3-0 win over Southampton on Saturday. Ten Hag said the Argentina international ‘downsized’ Southampton with his display. Goals from Matthijs de Ligt, Marcus Rashford and Garnacho gave Man United the victory over the hosts. “Of course, we are happy when you bring a sub on who has an impact and he [Garnacho] was the one who downsized the opponent to 10 with a good action and then a good finish,” Ten Hag told MUTV. “I think also the rest [of Garnacho’s performance], I was…