The Porto goalkeeper reached the landmark when he started his side’s opening Group D match against Schalke in Gelsenkirchen.
The game finished 1-1 with the hosts opening the scoring just past the hour mark through Swiss striker Breel Embolo. Casillas’ Porto, however, earned a point through Brazilian midfielder Otavio’s 75th minute penalty.
With the start, Casillas went past Manchester United great Ryan Giggs, who played in 19 Champions League campaigns.
Rounding out the top three is another United legend, Paul Scholes, who took part in 17 seasons in Europe’s premier club competition.
Iker Casillas 👏👏— FC Porto (@FCPorto) 18 September 2018
Recordista isolado de participações na Champions League👉 20
Estreia▶ 15-09-99 vs. Olympiacos#FCPorto #UCL #S04FCP #IkerCasillas @ChampionsLeague @IkerCasillas pic.twitter.com/yNHYlK3btz
Casillas, 37, played in 16 of his Champions League campaigns with Real, and is now embarking on his fourth with the Portuguese side.
The former Spain international has won the competition three times: in 1999/00, 2001/02 and most recently in 2013/14, all of which of course came while playing for Los Blancos.
With Porto, Casillas has managed to get out of the group stage in the past two seasons, but the team was knocked out in the round of 16 both times.
He has been more successful on the domestic front, helping the Portuguese giants to a league title last term.
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