Four clubs. One trophy. Both ties wide open going into the second legs.

We previewed these ties last week. Bayern were favourites for the trophy, PSG carried the champions' aura, Arsenal looked unbeatable, Atlético looked like Atlético. Then the first legs happened — and somehow made every one of those takes look both right and wrong at the same time.

A wild 5-4 in Paris. A tense 1-1 in Madrid. Eleven goals across the two ties, more tactical curveballs than anyone expected, and a final that's genuinely impossible to call. Below is everything from the original preview, plus what we've learned and where our model now sits for Tuesday and Wednesday night.

Let's get into it.

PSG — the defending champions

Paris did what no French club had ever done last May. Lifted the trophy, ended the Mbappé era, rebuilt entirely under Luis Enrique's vision, and somehow came back even better. That takes a special kind of institutional confidence.

The journey to the semis wasn't smooth. A league phase that finished 11th, only sneaking into the play-offs. They were beaten by both Bayern and Sporting CP in the autumn, drew games that felt like dropped points. Then something clicked. A rampant 8-2 aggregate demolition of Chelsea in the Round of 16, followed by a composed 4-0 over Liverpool in the quarters. The team that won it last year arrived just in time.

Marquinhos, still the beating heart of this defence at 31, anchors everything alongside the underrated Willian Pacho. Nuno Mendes and Achraf Hakimi aren't really full-backs anymore — they're auxiliary midfielders and wingers who happen to start wide. Vitinha (injured for the first leg) and João Neves are the engine. And up front, Dembélé, Barcola, Doué and the extraordinary Khvicha Kvaratskhelia — the standout performer of the entire tournament so far.

Bayern — the team with a point to prove

Under Vincent Kompany — now in his second season — Bayern have rediscovered the devastating, high-octane football that defined their treble eras. They were eliminated in the quarters last year, finished outside the league phase top eight, and arrived at this campaign with something to settle. They've settled it emphatically.

A 10-2 aggregate steamrollering of Atalanta. Then a 6-4 epic against Real Madrid in the quarters — a tie that had absolutely everything. Bayern were behind. Bayern came back. Bayern were brilliant. The architect, of course, is Harry Kane — 16 goals in his last 15 UCL games, almost a goal a game in the competition. Michael Olise on the right is the most exciting wide player in European football right now. And Luis Díaz, somehow signed from Liverpool last summer, gives Kompany a different option on the left. With Musiala still recovering from a fibula fracture, Kane has carried the attacking burden — and carried it without complaint.

What we learned in Paris

A 5-4 was not on most people's bingo card. The two best attacks left in the competition delivered nine goals between them, and PSG just edged it. Without Vitinha to control the midfield, the structure was looser than Luis Enrique would have liked — but Kvaratskhelia, Dembélé and Doué picked Bayern's makeshift back line apart anyway. Bayern, for their part, refused to die. Kane, Olise and Díaz kept finding ways back into the match. It was thrilling. It was also a defensive horror show on both sides.

The model now sits a touch on the Under for the second leg — at 4.33 for Under 2.5 (our heroPick on the Bayern v PSG match page), the kind of price you'd expect after a 5-4. The logic: both managers know they cannot afford another open game. Bayern need to score twice without conceding more than once and will likely play with more midfield discipline. PSG just need a draw and can absorb pressure. Tighter game, tighter referee, tighter expected total.

That said, the Allianz Arena under floodlights with Kane needing a hat-trick is hardly a recipe for a 0-0. The over/under call here is about as close as it gets — and the value has shifted toward the Under since the first-leg fireworks.

Arsenal — three years in the making

There is a version of this that ends in either triumph or therapy, depending on your emotional constitution. Arteta's side have been building toward this for three years. Two seasons ago, quarter-finals. Last year, semi-finals — eliminated by PSG. This year, they arrive with the most extraordinary record left in the competition: the only unbeaten team. Ten wins and two draws from twelve games. A perfect 8-0-0 league phase, the first side in UCL history to manage it.

The Viktor Gyökeres factor deserves a headline of its own. The Swedish striker, signed from Sporting last summer, is the missing piece this attack needed. Around him: Saka, one of the three or four best right wingers in world football right now; Martinelli, relentless on the left; Ødegaard pulling the strings. And the foundation — Saliba and Gabriel, arguably the best centre-back partnership in Europe. Raya outstanding. White and Timber elite at full-back. Arsenal average a goal conceded every other game in this competition.

One word of caution. The 1-0 aggregate against Sporting was tight. And Arteta's men have a habit of making ties more nervous than they need to be. Atlético will have noticed.

Atlético — Simeone, year fourteen

Diego Simeone has been managing Atlético since December 2011. Read that again. Two La Liga titles, two Europa Leagues, two Champions League finals — and yet, somehow, the biggest prize of all continues to elude him.

Simeone has spent a career finding ways to beat teams better than his. The discipline, the structure, the psychological fortitude, the transition football that punishes the smallest mistake. And this season, he has something he hasn't always had: goals from everywhere. Julián Álvarez has been extraordinary — three goals and two assists across two legs against Spurs in the Round of 16, fifteen UCL goals in his last nineteen appearances. Sørloth provides a different physical presence. And Griezmann, at 35, still reads games ten seconds before anyone else.

The route here was extraordinary too. 7-4 against Brugge. 7-5 against Tottenham. Then a 3-2 aggregate over Barcelona — who beat them at the Metropolitano in the second leg, but couldn't overturn the deficit from the Camp Nou. Simeone's team go to Wanda when they need to.

What we learned in Madrid

Atlético got exactly the platform Simeone wanted. A draw at the Metropolitano against the tournament's only unbeaten team is a reasonable result on paper — but with the away goals rule abolished since 2021/22, a 1-1 is genuinely level. No advantage to the team that scored away from home. It's effectively a one-off semi-final at the Emirates, with extra time looming if it stays tight.

Arsenal will see the second leg as a chance to settle this on home soil, where they have been the more dominant side all season. The model agrees — backing them at 1.62 to win on the night. Atlético, of course, will travel with the same defensive blueprint that earned them the draw in Madrid: deep block, narrow shape, lethal on the counter through Álvarez and Sørloth. If Arteta's men can't break that down inside 90 minutes, Simeone will fancy his chances in the lottery that follows.

The updated PicksIQ verdict

PSG are now narrow tournament favourites. A 5-4 first-leg lead, the away-leg done, and the cushion of needing only a draw at the Allianz to reach the final. The defence still looks shaky — but Vitinha's likely return tightens the midfield, and Kvaratskhelia is operating on a level no one has been able to live with. Defending champions, with one foot in another final.

Arsenal are exactly where they wanted to be. The unbeaten run is intact, the second leg is at home, and our model has them at 1.62 to dispatch Atlético on the night (xG 3.00 vs 0.74). Get past Tuesday and Arteta's side likely wait for whoever survives Munich. Three years of building toward this; one 90-minute win away from a Champions League final.

Bayern have the harder job now but the better stage to do it on. Two clear goals at the Allianz under floodlights with Kane in the form of his life is hardly a fantasy. The model leans toward Under 2.5 in this specific second leg (4.33) — a tighter, more disciplined game than the Paris madness — but a 2-0 or 2-1 home win is the exact scoreline that gets them there.

Atlético are still Atlético. The 1-1 draw in Madrid was professionally executed — exactly what Simeone needed. Ask yourself whether you'd enjoy travelling to the Emirates to play a fully-loaded Arsenal that must score, then ask whether Simeone enjoys nothing more than that exact scenario. We rate them more dangerous than the price suggests.

Our model's final? PSG vs Arsenal. The defending champions, who have already proved they can beat anyone left, against the only unbeaten side in the competition. Kvaratskhelia vs Saliba. Doué vs Saka. A rematch of last year's semi — but this time with the roles reversed and an Arsenal side that has spent twelve months learning exactly what they needed to from the defeat. Budapest, late May. Genuinely cannot wait.

Odds correct at time of writing from Oddschecker — always check the latest before placing. Please gamble responsibly. BeGambleAware.org. 18+.