James Rodriguez

Colombia's James Rodriguez celebrates a goal during a June 28 World Cup match with Uruguay in Rio de Janeiro. (Paolo Aguilar / EPA / June 28, 2014)

A riveting World Cup resumes Friday with no end to the drama in sight.

For all of the wacky results in the pre-knockout phase, the round of 16 played to form -- even as it took a while, with five of eight matches spilling into overtime and a sixth decided on a goal deep into extra time. Every group titlist moved on, and it is no stretch to see any but one of them from a high-pedigreed quarterfinals cavorting in the winner's circle on July 13.

The outlier is Costa Rica, which has gone 3-0-1 with smoke, mirrors, grit and sublime goalkeeping. If the Costa Ricans do not wake up and freak out over the company they are keeping, a competitive game with the Netherlands is conceivable but unlikely.

France started gangbusters but has cooled, which gives more even-keeled Germany an edge in their Euro two-step. A shortage of speed along the back line is a German concern, but the French might lack the giddy-up to exploit it.

Argentina-Belgium fascinates. The Belgians have been dented for one goal, excluding penalty kicks, which means Lionel Messi will be hard-pressed to make magic with his less-than-supporting cast. Messi has taken a while to crank it up, and Belgium waits forever to start scoring. So this match could turn from uneventful to electrifying on a dime late in the second half.

An upset may be brewing: Colombia has impressed far more than its opponent, Brazil, outscoring foes 11-2. James Rodriguez stands in front of the line for MVP candidates. This team has displayed no weakness -- unlike the tournament hosts, who have proved vulnerable in the back and have hung hard-working Neymar out to dry up front.

Nonetheless, Brazil remains the favorite at odds of 11-4 to take the Cup. Then comes Germany (7-2), Argentina (4-1), the Netherlands (9-2), France (7-1), Colombia (11-1), Belgium (12-1) and, a kilometer behind them all, Costa Rica (40-1).