Pulisic earned the penalty himself, after being bundled over in the area, and Christian made no mistake from 12 yards. His goal came after Giovanni Reyna had handed the States a first-half lead, before Niall McGinn pulled one back for the hosts with just a couple of minutes remaining.
Elsewhere, Andreas Christensen watched on from the bench as Denmark recorded a big victory over Moldova. The Danes were 5-0 up at half-time before adding a further three in their resounding 8-0 win.
Earlier today, Kurt Zouma put in an assured performance at centre-half as he helped France to a comfortable 2-0 away win against Kazakhstan.