How the New Champions League Format Has Changed Tactical Approaches in the Knockout Round

UEFA's revised Champions League format, in its second season of the 36-team league phase, has produced measurable tactical shifts in how clubs approach the knockout stages. The round of 16 matchups, drawn on February 21, feature three fewer cross-league pairings than in the previous group-stage era and significantly more balanced aggregate pairings, per FiveThirtyEight's club-strength model published in March.

Clubs advancing through the league phase now enter the knockouts with more varied match experience — 10 opponents rather than 3 — and with better calibration to non-league-specific opposition. The tactical consequence has been a visible narrowing of the gap between the continent's elite clubs and the next tier.

The League Phase Data Advantage

Each club entering the round of 16 has now played 10 matches against distinct opponents from across Europe. In the previous format, a club faced only three league-phase opponents repeatedly. The new structure has rewarded clubs that collect comprehensive tactical data on non-traditional rivals.

Manchester City's analytics department expanded by 18 percent in 2025 to accommodate the expanded data set, according to a Guardian report in January. The club's head of analysis, Ed Sulley, told the newspaper that the new format "rewards processing depth more than playing quality at the margin."

The End of the Two-Leg Bias

Historical two-leg knockout analysis has long suggested that the home-second leg team holds a slight advantage, estimated at 52.5 percent by an Opta study covering 2003-2023. The new format's knockout playoff round — introduced for teams finishing ninth through 24th in the league phase — has amplified this effect, producing a 58 percent home-second win rate since its introduction in 2024-25.

UEFA has launched an internal review of whether to retain the single-draw knockout bracket format or return to open drawing after each round. The review is scheduled to conclude ahead of the 2027-28 season. Several club executives, including Barcelona's Joan Laporta and Bayern Munich's Herbert Hainer, have publicly supported retaining the bracket.

Low-Block Tactics in the Round of 16

Tactical diversity has increased measurably since the format change. The round of 16 has produced more low-block defensive performances from away teams in the first leg: 36 percent of first-leg away performances this season featured fewer than 40 percent possession, up from 24 percent in 2022-23, per Opta data cited by The Athletic.

Bayer Leverkusen manager Ronny Wasmuth, who replaced Xabi Alonso at Leverkusen in June 2025, ordered a 4-4-2 low block for his club's first-leg tie away at Atletico Madrid on March 4. Leverkusen completed only 31 percent of passes and had just three shots but secured a 0-0 draw. Wasmuth told Kicker: "Sometimes you play for the second leg, and that's fine."

Inverted Wing-Back Systems

Mikel Arteta's Arsenal, the only English side in the 2025-26 round of 16, has used an inverted wing-back system in Champions League knockouts that differs from its Premier League structure. Right-back Ben White has been tasked with moving into central midfield in possession, giving Declan Rice more freedom to press up the pitch.

The adjustment is a specific response to European opponents' preference for back-three buildups, which Arteta considers less well-positioned to combat the central overload. Arteta explained the choice in a February press conference: "In the Premier League, the ball goes side to side. In Europe, it goes up the middle. We have to defend the middle."

Set-Piece Emphasis

Set-piece scoring has risen by 11 percent in the Champions League knockouts compared with the pre-format-change era, per UEFA's technical report published in January. Six of the 16 round-of-16 first-leg goals in 2025-26 came from corners or free kicks — a rate significantly above the 23 percent set-piece share across Europe's top five domestic leagues.

Teams with dedicated set-piece coaches have gained an edge. Brentford, which pioneered the role in 2021, now has five of its alumni working as dedicated set-piece coaches at other top-flight clubs: Manchester United, Liverpool, Real Madrid, Aston Villa and Inter Milan. Thomas Gronnemark, the Danish set-piece specialist who worked at Liverpool under Klopp, has consulted for nine different Champions League-level clubs since 2023.

Outlook for the Quarterfinals

The round of 16 aggregate matchups produced two upsets in the first legs: Borussia Dortmund's 2-0 away win at Paris Saint-Germain and Atalanta's 1-1 draw at Real Madrid. Both return legs — scheduled for March 11 and 12 — will shape the quarterfinal bracket and the perceived strength of the competition.

Manchester City, Arsenal, Barcelona, Bayern Munich, Inter Milan and Atletico Madrid are favored to reach the quarterfinals, per Opta's supercomputer projections. Real Madrid remains the favorite to win the competition at 26 percent probability, followed by Manchester City at 19 percent and Arsenal at 13 percent.