Jose Mourinho led Real Madrid to the Primera Liga title and promptly claimed it was the toughest of his career.
Real sealed their 32nd crown - and their manager's seventh domestic league title - with an emphatic 3-0 win at Athletic Bilbao.
And despite having already won league championships with Porto, Chelsea and Inter Milan, Mourinho believes Barcelona's brilliance makes this his sweetest victory yet.
The 49-year-old told RealMadridTV: "I won the league title in Portugal, Italy and England, but this one has been the toughest.
"I've won seven league titles overall and I know what it feels like.
"Barcelona won all their games, as befits the great team that they are. They've been winning to the very last day.
"They are a club with great tradition that knows we deserved to win this title."
Mourinho added: "We have to celebrate this championship but then we have to continue working because next season will also be tough."
Midfielder Xabi Alonso also feels the calibre of Real's opponent in the race for the league title makes this achievement even more special.
The 30-year-old Spain international said: "We finally managed to win La Liga. We competed all season with a great opponent like Barcelona, and that's why there's so much merit in winning the title.
"We've been regular and consistent. I dedicate this to my family, friends and all Madridistas."