Venezuela claimed an extra time win over the United States at the FIFA Under-20 World Cup ©Getty Images

Venezuela and Uruguay both secured their places in the semi-finals of the FIFA Under-20 World Cup with narrow victories in South Korea today.

Both quarter-finals needed extra time to reach a conclusion.

The Venezuelans eventually defeated the United States 2-1 at the Jeonju World Cup Stadium.

The South Americans dominated the match but were wasteful in front of goal as the game finished goalless after 90 minutes.

In the first half, Venezuela's Sergio Cordova thought he had opened the scoring but, after the officials consulted the Video Assistant Referee (VAR), he was found to have been marginally offside.

Cordova's team-mate Ronaldo Chacon struck the bar within three minutes of the second half beginning before the former also saw a shot rebound off the frame of the goal. 

Erik Palmer-Brown almost snatched victory for the Americans but he failed to properly connect with a header, which proved to be the final touch of the 90 minutes.

It took just six minutes of extra time for the first goal to arrive as Adalberto Penaranda put Venezuela 1-0 up.

Nahuel Ferraresi then doubled the South Americans' lead with five minutes remaining.

Jeremy Ebobisse cut the deficit a minute later, but Venezuela held on to book their place in the final four.

Uruguay beat Portugal on penalties to reach the final four ©Getty Images
Uruguay beat Portugal on penalties to reach the final four ©Getty Images

They will now play Uruguay in the semi-finals after they defeated Portugal in a penalty shoot-out following a 2-2 draw at the Daejeon World Cup Stadium.

Xande Silva scored after just 55 seconds for Portugal, the eighth-fastest goal in the tournament's history, with a chipped shot past Santiago Mele.

Santiago Bueno equalised for Uruguay 15 minutes later with a close-range header after Nicolas Schiappacasse's volley from a corner had hit the crossbar.

Portugal then regained the lead courtesy of a sublime effort from Diogo Goncalves on 41 minutes.

He cut in from the left wing and unleashed a stunning effort into the far corner.

Uruguay fought back once again, this time with a penalty early in the second half after Yuri Ribeiro fouled Agustin Canobbio in the area.

Federico Valverde slotted home the spot kick.

Neither side could find the winner in regulation or extra-time, so penalties in the new "ABBA" format decided the outcome.

Under the new system, after the first team has taken their opening kick both sides take back-to-back penalties until they have taken five apiece.

Mele made two saves in the shoot-out with Bueno eventually scoring the winner to earn a 5-4 success. 

Quarter-final action is due to continue tomorrow with England against Mexico and Zambia against Italy.