Khachanov won the pair's previous encounter in Paris - at 2018 Paris Masters, when the Russian claimed a straight-set win in the final to clinch the biggest title of his career until now.
Alba's natural replacement in the Barca squad, Junior Firpo, is also injured at the moment, although he is expected to be able to return to training in the coming days. Enditem
"We will see several unusual results not only in the Bundesliga but all over Europe. I think we are ahead of an exciting season," the 60-year-old predicted.
"We are in a very strange situation, after a lot of months without much tennis, especially for me, that I didn't play in America, I don't know if it's a positive thing or a negative thing," Nadal said when asked how important it was to keep the early-round matches short and sweet.
That performance has put Athletic coach Gaizka Garitano under pressure and both he and Machin need wins to assure they are still in their jobs after the international break.
Bratislava's budget is significantly smaller this season and the team from Slovakia's capital city got considerably younger with only three players older than 25 years and features only three foreign names.
After leading 65-61, Shanxi rode on a 10-3 surge midway through the last quarter and withstood Hebei's comeback afterwards.
Nadal will face Sebastian Korda, the son of 1998 Australian Open winner Petr Korda, in the next round. The American youngster secured his first appearance in a Grand Slam round of 16 by beating fellow qualifier Pedro Martinez 6-4, 6-3, 6-1 to advance.
Tianjin coach Liu Hao admitted as a young team, his side have a gap to Shanghai in terms of skill.
Shanxi led 24-16 in the first quarter, seeing Hebei trail by five points before the half break.
"I'm living in a dream. I came here two weeks ago to my Roland-Garros qualifying but today I'm here in the quarterfinals," said the 26-year-old Italian qualifier, who hadn't played a Grand Slam main draw before this year's Australian Open, where she suffered an early first-round exit.