Jhon Arias scored the only goal as Colombia beat Ghana 1-0 in sweltering conditions in Kansas City on Friday to reach the World Cup last 16, continuing a quietly impressive campaign that has established them as dangerous outsiders.

Arias struck in the 14th minute, guiding home a cross from substitute Luis Suarez, and Colombia`s disciplined defence did the rest as Nestor Lorenzo`s side extended their unbeaten run and booked a meeting with Switzerland in the next round.

Colombia had largely flown under the radar at the tournament, despite going undefeated against Portugal, Uzbekistan and DR Congo to top Group K.

Their breakthrough on Friday came from two players who had not been expected to combine, as Suarez, thrust into action after Jhon Cordoba was forced off with an apparent groin injury in the eighth minute, delivered a pinpoint cross to the back post where Arias had somehow drifted unmarked.

With time and space to pick his spot, Arias calmly guided the ball into the bottom corner to hand his side a deserved lead.

The stadium felt more like Barranquilla than Kansas City as tens of thousands of Colombia supporters turned the clash with Ghana -- a team ranked 60 places behind them -- into a de facto home game, giving the South Americans a level of support rarely seen so far from home.

The stands were a writhing, dancing sea of yellow jerseys, twirling scarves and black-and-white sombrero vueltiao hats, that many used to fan their faces in the oppressive 30 degrees Celsius (86 F) heat.

They bounced in unison, roared their team forward with every attack, and regularly broke into chants of "Vamos Colombia! Esta noche tenemos que ganar!" (Let`s go Colombia, tonight we have to win).

They need not have worried. Colombia were the better team by some distance.

Luis Diaz had numerous scoring chances. He fired into the side netting in the first half, then celebrated what he thought was the game`s second goal early in the second half when he slotted home Arias`s cross, but it was disallowed for offside.

Lorenzo`s men continued to push for a second goal, and Ghana goalkeeper Lawrence Ati-Zigi, who was excellent all night, made one terrific save after another in the dying minutes as Colombia`s fans cheered every one of their team`s touches of the ball.

Antoine Semenyo was Ghana`s biggest attacking threat, yet Colombia`s disciplined defence denied him a clear sight of goal.

Los Cafeteros became the fourth South American team to reach the last 16, joining surprise package Paraguay, who stunned Germany, along with Brazil and Argentina, both of whom survived scares of their own.

Colombia play the Swiss on Tuesday in Vancouver.

The match also marked the first time in tournament history that both teams were forced to make a substitution before the 15-minute mark due to injuries, as Ghana right back Marvin Senaya limped off with a hamstring injury in the 13th minute.