The two-goal hero lauded his team-mates, despite stealing the show as they defeated Uruguay, and acknowledged that Brazil will be their toughest test yet
Two goals from the Monaco forward propelled Jose Pekerman's men to a 2-0 win and into the last eight of the tournament, where they will face hosts and favourites Brazil, but it was his first strike that truly lit up the Maracana.
The 22-year-old scored arguably the goal of the tournament, chesting down with his first touch before swivelling and volleying into the back of the net via the crossbar from 25 yards out.
James, who now sits top of the Golden Boot leaderboard with five goals from four games, acknowledged that Brazil will be a far tougher test and lauded his team-mates for their assistance as he stole the show in Rio in the 2-0 triumph.
"It's a historic success," James told Sky Sport. "Now comes the most difficult moment for us so far, we hope to get past the last eight though.
"The entire team did well, my team-mates were all crucial. We created many chances due to the speed and pace of the entire team."
Colombia looked impressive in the group stage, topping their draw ahead of Greece, Cote d'Ivoire and Japan with three wins out of three.
They will be looking for a fifth World Cup 2014 win in a row when they face Brazil on July 4 - who needed penalties to see off a battling Chile side in their game earlier on Saturday.