Always the bridesmaid. The Champions League perennial losers were at it again in Portugal, to leave themselves facing the possibility of another early exit.
Juventus put every single egg they could cobble together in a basket filled to the brim to persuade Cristiano Ronaldo to come to Turin for one last hurrah and bring Champions League glory to the club for the first time in a quarter of a century.
Ronaldo, of course, has played his part. In his two-and-a-half seasons in northern Italy the goals have continued to flow. The problem is he has had very little help in his quest to earn this giant of the game more than the two European Cup crowns they have mustered in their history.
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The seven-time losing finalists' next move to remedy their continental woes was to bring in Andrea Pirlo as coach to replace Maurizio Sarri at the end of last season, despite the former Chelsea boss having guided his side to a ninth-straight Serie A title.
It was Ol' Big Ears that the club wanted. But Juventus' poor, unimaginative showing in Porto was just the latest episode in a troubling saga at the once great club. Domestically, Juve are fourth, eight points off the top - uncharted territory for the champions - and now another early exit from the Champions League looms large. Federico Chiesa's late goal masked what was another disappointing display from Pirlo's Juventus, and means they live to fight another day. But on this evidence in the Estadio do Dragao, Pirlo's side don't possess the necessary quality to overturn the deficit in a few weeks, even at home.
Porto are no slouches, and are always underestimated in this competition, given how few people across the rest of Europe see them play on a weekly basis. Sérgio Conceicao's side came into the contest having conceded in just one of their six group-stage games on their way to the last-16 - away at runaway Premier League leaders Manchester City.
But this is Juventus we are taking about. A team who have won the last nine-successive Scudettos, who were comfortably second best against a team supposedly inferior to them - and not for the first time this season.
After their defeat to Inter MIlan on January 17, Juventus looked to have turned the corner and got themselves back to their relentless best, winning the next six games in a row in all competitions, conceding one goal in that run.
Ronaldo was at the forefront of such fine form, of course, but at least he had support from Paulo Dybala, Chiesa, Weston McKennie, and even forgotten man Aaron Ramsey.
Last weekend, however, Juve offered such little threat in attack and gave away a sloppy goal as they fell to a 1-0 defeat to Napoli, undoing all their earlier good work, before more mistakes cost them right from the off in Porto.
There is no excuse for the slack pass from Rodrigo Bentancur to allow Mehdi Taremi in for Porto's opener after just 63 seconds, and then to have not switched on at the start of the second half as Porto made in two 19 seconds after the interval was almost unfathomable at this level.
The goals typified Juve's season, as did the lack of imagination that followed. Pirlo seemed to get his team selection all wrong, too. The team that took to the pitch was Juventus' youngest starting XI (27y 122d) in a Champions League knockout match since the 1997/98 final against Real Madrid (26y 353d). And it showed.
The onus was again on Ronaldo, and he could not deliver. But he cannot do it all on his own. Somehow Juve are still in with a chance of reaching the last eight, but Pirlo is going to have to come up with something very different indeed to turn this tie around.