Alberto Undiano Mallenco made his debut in the Primera Division in October 2000 at the early age of 26. From 2004 and on he officiated in UEFA Cup matches and qualifiers. Mallenco got his first Champions League match in 2007, and a big one too: Bayern vs Spartak Moscow. That was the year he became an Elite Category referee.
Alberto Undiano Mallenco was the referee in the semi-final of the UEFA U21 Championship in 2006 (10 yellow cards!), and the final of the FIFA U20 World Cup 2007 in Canada won by Argentina (against the Czech Republic 1-2).
1994/1995 (Third Division)
1995/1996 (Second Division B)
1997/1998 (Second Division A)
2000/2001 (First Division, the youngest Spanish ref ever)
Since 2004 FIFA referee
Alberto Undiano Mallenco took charge of three matches in the 2010 World Cup in South Africa.
Unlike his colleague Velasco Carballo, Undiano wasn't selcted for Euro 2012, but together with Velasco's his name did appear on the list of 52 for the 2014 World Cup.