Here we take a look at some of the key facts and figures from the 46-year-old Spaniard’s professional footballing career…
1) He has never lost against Blues in the eight times he has faced us as manager - winning three of those matches and drawing five, at an average of 1.75 points a match.
2) During his time at Middlesbrough he won the Football League Championship Manager of the Month three times in 2015 - January, September and December.
3) He spent the 2006 Major League Soccer season as a player with the Colorado Rapids.
4) His main position during his playing career was a centre-half, but he could also fill in at left-back.
5) He has a younger brother called David who was also a footballer (a striker), but he mostly played in the Spanish lower leagues.
6) As a player with Real Madrid he won the Champion's League three times, La Liga once and the Spanish Super Cup twice.
7) He only played once for Spain at senior level, on 26 April 1995 against Armenia for the UEFA Euro 1996 qualifiers. However, he also featured for the Basque Country, the national team of the Basque autonomous community, making six appearances.
8) He featured four times for the Spain Olympic team in the 1996 Summer Olympics in Atlanta, before Spain lost out in the quarter-finals.
9) His first coaching role in domestic football was with his former club Real Madrid. He was appointed to the role of assistant manager in June 2010 by Jose Mourinho, with whom he spent three years.
10) He retired from playing in March 2007.
11) He appeared in 275 La Liga games over the course of 13 seasons.
12) He was born on September 18, 1973 and his star sign is Virgo. He was born during the Chinese year of the Ox.
13) Karanka took charge of Spain Under-16s for two years before he was appointed as Jose Mourinho’s assistant at Real Madrid in 2010
14) He turned down the opportunity to join Jose Mourinho as his assistant at Chelsea to embark on his own management career.
15) His preferred formation as a manager is 4-2-3-1.
16) He spent 1219 days as manager of Middlesbrough, where he took charge of 169 matches, winning 80 of them, drawing 40 and losing 49 at an average of 1.66 points per game. He also used 73 players through that period.
17) He spent 368 days as Nottingham Forest manager, taking charge of 52 matches – with 17 wins, 18 draws and 17 losses at an average of 1.33 points per match. He used 48 players during his time at Forest.