Defending champions United States are one of three sides that remain unbeaten following the quarter-finals of the FIBA Under-19 World Cup ©Getty Images

Defending champions the United States and their North American neighbours Canada both stayed unbeaten at the International Basketball Federation Under-19 World Cup, albeit in contrasting fashions.

The US have been the team to beat in the tournament so far and ran out convincing 88-58 victors against Senegal in their quarter-final at the Olympic Sports Center in Riga, Latvia.

After winning the opening quarter by 32 points to 14, the US were in cruise control for the rest of the contest, eventually triumphing by a 30 point margin.

Meanwhile, Canada edged to a 81-77 win over Spain, recovering from trailing by a point after three quarters of play.

The Canadians came up with the goods under pressure and won the final quarter 23-18 to turn the contest around in their favour.

The third side with a 100 per cent record heading into the knockout stages of the tournament were Serbia who survived a spirited fourth quarter performance from Argentina to win 89-83.

The closest contest of the day saw France recover from a six point deficit after quarter one to defeat Lithuania 84-79 after one period of overtime.

Lithuania led 21-15 after the first quarter, before France won the next two quarters, both by four point margins, to take a two point lead.

Lithuania then claimed quarter four by 18-16 to make the score level at 69-69 at the end of regulation play.

France won the first period of overtime 15-10, and progressed to the semi-finals tomorrow where they will face Serbia, with the United States and Canada meeting in the second last four encounter, a repeat of the 2017 semi-final, that was won by the Canadians.

Elsewhere today the first classification matches took place, with eight teams involved in the first of three days of games that will determine places nine to 16 at the tournament.

In the first round of classification matches Australia ran out handsome 95-52 winners against Puerto Rico, Iran overcame Mali 71-59, hosts Latvia convincingly beat Korea 90-67 and Turkey were big winners over Japan 97-49.