Tennys Sandgren
He comes after a long and tiring match in the company of Dominic Thiem, which he has managed to pass, in a decisive set. That game needed 53 games to determine the winner.
In the match with Thiem, the American maintained a good percentage on the first service, 79%, and the second had 57%. I think that this time the percentages will be significantly lower, given the accumulated fatigue.
Perhaps the victory against Thiem is not such a big surprise if we think Tennys is also responsible for Wawrinka’s homecoming in the second round.
With his present in the quarter here in Melbourne he has managed to raise more money than the total of his team up to now throughout his professional career.

Hyeon Chung
He comes after a 3-0 win in the company of Djokovic, one of the favorites to win the trophy. 38 games were played in that game.
With 65% on the first service, Chung does not impress very hard, but the fast field and corner kicks have made the audience delight in the previous match, and Hyeon will wear these weapons in the quarter-finals.
Like his opponent, Hyeon is a pleasant surprise for this tour; he has never crossed the 3rd round of a grand slam tour yet, and this year’s performance will help him climb into the ATP hierarchy.
He is a defensive player, and this was best seen against Djokovic. Although the matchup favored the Serbian theoretically, the South Korean has found the resources needed to spoil the former Melbourne winner.
Direct meetings
The two met again in Australia this year, in Auckland this year. At that meeting, Chung set himself in the decisive set at the end of 30 games.

My tip: Tennys Sandgren v Hyeon Chung
It will be a balanced match, as was the one in Auckland, but this time I think Chung’s game will work better if we report what he has shown against Nole.
Hyeon returns very well, I dare say better than Thiem, and that makes him a fairly dangerous opponent for Tennys.
Sandgren is the strongest player of the two, but Hyeon is not too far away, so I expect to see a nice duel in the number, and I think the statistics will be echoed here.