Jason Pine: Who will triumph in tonight's knockout round?

Ghana team player's celebrate after defeating Argentina 3-2 in their U20 soccer World Cup match in Wellington, New Zealand, Tuesday, June 2, 2015. (AP Photo/Ross Setford)

The first four round-of-16 matches are played today, with some intriguing match-ups in prospect.

Ghana v Mali - 4pm, Wellington

A mouth-watering all-African clash awaits in Wellington with Ghana's attacking qualities set to test a solid Malian rearguard.

Ghana were excellent in pool play, beating Argentina and Panama to top group B, marking themselves out as both an eye-catching and effective footballing side. They are adept at keeping the ball and fashioned several goal-scoring opportunities in all three of their pool games.

Mali finished level on points and goal difference with Uruguay in Pool D and were only relegated to third through a drawing of lots. They certainly can't be discounted after a win over Mexico and a draw with Uruguay and finished above Ghana in group play during the African qualifiers for this tournament, beating them 1-0 in their group clash.

Key man: Clifford Aboagye (Ghana): The elegant midfielder plays his club football in Spain and was a member of the Ghana side that finished third in this tournament two years ago. Much of Ghana's attacking play involves his creativity and passing.

Tip: Ghana 2-0

Serbia v Hungary - 4pm, Dunedin

Serbia topped a tight Pool D with impressive 2-0 wins over Mali and Mexico. They have been typically hard to break down, conceding just once in pool play and repelling the best efforts of a variety of attacking opponents. They'll be well-used to this venue now too, having played all of their matches under the roof at Dunedin Stadium

Hungary started the tournament with a bang, blasting five past Korea DPR in their opening match, but then suffered back-to-back losses to Brazil and Nigeria and only squeaked into the round of 16 on goal difference. They had patches of dominance in both losses though and certainly won't be easy-beats in a knockout match.

Key man: Bence Mervo (Hungary): The classy striker scored a brilliant hat-trick in the opening game against Korea DPR and also put his side ahead early in their clash with Brazil. He seems the most obvious source of goals for his side.

Tip: Serbia 1-0.

USA v Colombia - 7.30pm, Wellington

A cracking contest is in store here between two sides who finished second in their respective pools. Colombia could perhaps be slightly more match-hardened after emerging from the hotly-contested Pool C. Their football is entertaining, but the end-product hasn't always been there, as evidenced by just three goals so far.

USA looked every inch a tournament threat in their victories over Myanmar and New Zealand in pool play, but were very much second-best against Ukraine last time out, even though their progress to the knockout stages was assured by then. They'll need to regain their early tournament form to compete with the classy Colombians.

Key man: Juan Quintero (Colombia): The Colombian captain is an assured defender who marshals his backline superbly.

Tip: Colombia 2-1 after extra-time

Ukraine v Senegal - 7.30pm, Albany

The Europeans will be heavily favoured here after coming through group play without conceding a goal to top Pool A. After failing to break down New Zealand in the opening match, Ukraine impressed against Myanmar and particularly USA and have become a dark horse for the title.

Senegal came through a tough pool, recovering from conceding a goal inside 30 seconds in their opening match against Portugal to draw with Colombia and beat Qatar. They appear to be the weakest of the African sides at the tournament and will have to lift their performance to have a chance of progressing to the last eight.

Key man: Viktor Kovalenko (Ukraine): The classy striker scored a sublime second-half hat-trick against the USA and leads the Golden Boot standings with five goals so far in the tournament.

Tip: Ukraine 2-0