Juventus’ defence remains a riddle most teams in Europe are unable to solve.

The Serie A champions held Monaco scoreless in a 2-0 away win in the first leg of their UEFA Champions League semi-final tie.

The result was Juventus’ six straight clean sheet in the competition, which sets a new club record in Europe’s top continental club tournament.

The last club to score against in the Champions League against Juventus was Sevilla, back on November 22, in a 3-1 loss to the Old Lady. Since that time Dinamo Zagreb, Porto, Barcelona and now Monaco have all tried, and failed, to break down the Italian side’s brick wall of defence.

In fact, it was the first time high-flying Monaco, which put six goals past Manchester City and Borussia Dortmund in their respective Champions League ties, have been held off the scoreboard at home in all competitions since November 2015.

A big reason for Juventus’ success has no doubt been goalkeeper Gianluigi Buffon. And while his team’s defence can sometimes make life easy for him, the 38-year-old was at his best Wednesday. He made five saves in the contest – his best total since an outing against Sevilla in December of 2015.

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Monaco will again try to solve Juventus and Buffon on Tuesday, but will have their work cut out for them needing at least a 2-0 result to force extra-time at Juventus Stadium.