Now that the World Cup field is set, and the international breaks are over, it's time for the club season's final sprint. The top European leagues have comfortable leaders—except for Paris Saint-Germain, who is only four points up on Lens in Ligue 1—but there's still enough time for narratives there to flip. There are also domestic cups to be handed out, and trophies to be won or lost. However, the best drama left in the season is definitely in the Champions League, where at least half the quarterfinalists can reasonably convince themselves that they can win the whole thing, and the other four teams wouldn't need much hope to believe the same.

The draw has set up some juicy quarterfinal showdowns, with even more enticing semifinals on the horizon. There's a rematch of an exciting Copa del Rey semifinal, a showdown between the reigning continental champs and the most successful club in England, and the Champions League final boss of Real Madrid facing its second consecutive mega-challenge. There's plenty to talk about in each of these matchups, but let's start with the one that should, on paper, be the most lopsided contest, the one between the current Premier League leaders and...