Marvel Tales: Captain America #1

Synopsis

While Cap lounges around Avengers Mansion, thinking about Bucky and his place in the world, a gang of costumed thugs break in intent on stealing any secrets or weapons Stark may have lying about the place, to sell for profit. They figure Cap's "just an acrobat." They figured wrong! He mops up the place with them single-handed, then comments how lucky they were his partners weren't around... "They're really tough!"