Sen lunged, raising his hand and feet and the two entered a pretty impressive one-on-one. Well, two-on-one, because Jesse was definitely targeting Sen when he got the chance.
The two swords clashed. While Angelo was in no way more talented than Sen—this was someone who had killed hundreds with his bare hands and massacred thousands with weapons in Terran alone—he was able to hold on due to Jesse's assistance, as well as his weapons and equipment.
There were plenty of close calls, with Sen almost hitting him at his few openings. The dude was really fast and was a legitimate martial artist, in contrast to him, a civilian before the apocalypse. At some point, Angelo realized he could only defend himself and depend on his equipment to keep alive.
In fact, if he wasn't fully clad with armor and defense clothing from Lenny—a couple of extra equipment he could afford being one of Baron's cousins—he probably wouldn't be able to stand up right now.