The last derby was a rare off-day for Atletico Madrid – and for Luis Suarez.
On a run of seven wins in a row and two goals conceded, with no LaLiga defeats all season, Diego Simeone's men were second best in a 2-0 defeat last December. As for Suarez, his 73 minutes on the pitch yielded a single, wayward shot.
Still, that result turned out to be an aberration. Three months on, Atleti head into Sunday's game at the Wanda Metropolitano with a five-point lead over Real Madrid and Barca at the top of the table, and with a game in hand. Suarez, meanwhile, has scored 11 of his 16 LaLiga goals this term since that chastening day at Estadio Alfredo Di Stefano.
Suarez's form for Atleti has made a complete mockery of Barca's decision to cast him aside last year, the suggestion the striker was "too old" to be relied upon looking more foolish by the week as he spearheads their charge for a first league title since 2014.
Indeed, given his record against Madrid and the state of the league table, this weekend could be the moment Suarez tips the balance of the title race inexorably in Atletico's favour.
It wasn't simply being told to leave by Barca that left Suarez so incensed; it was being made to feel he was no longer good enough for "a great team".
"That's what I did not like," he told France Football. "If I hadn't done anything at a club like Barca for three or four seasons, I would have understood.
"But, every year at Barca, I scored more than 20 goals per season. I have always had good statistics, just behind Leo [Messi]."
So he is again. Suarez's 16 goals in 21 league games this term puts him second in the top-scorer standings, three behind Messi. Add in assists, and only his old team-mate (23) has had more direct goal involvements than Suarez (18) in LaLiga this season.
While Suarez is no longer as explosive as he was at Liverpool and in his earlier Barca years, he has lost little of his ruthlessness. Discounting the two penalties he has converted this term, Suarez has scored 14 times from an expected goals value of just 9.6. That differential of 4.4 is the biggest in the division, save for that of 'El Comandante', Levante's 33-year-old star striker Jose Luis Morales (5.0).
It follows that Suarez has a shot conversion rate (including blocked shots) of 23.9, the fourth-highest figure for any LaLiga player with at least 10 goals this season, the best being Roger Marti with 31.3.
The Uruguayan also boasts a big chance conversion rate of 63.2 per cent, having scored 12 out of 19 this term. No player to have scored from at least 10 big chances can match that success rate. That cutting edge in a team that has conceded just 16 league goals in 24 matches is a potent combination.
CAN SUAREZ STOP THE DERBY ROT?
Atleti followed December's derby defeat by winning 10 of their next 12 games, the only slip-ups being a Copa del Rey shock at Cornella and a 2-2 home draw with Celta Vigo on February 8 (in which Suarez scored twice).
However, including that result, they have won only twice in their past five league matches, a run that has emboldened Barca and Madrid's title hopes and left fans wondering whether 'Hay Liga' after all.
A dip in form before a derby is never positive, but Atleti in particular need no extra pessimism. They have not won any of the most recent nine league meetings with Madrid, their longest run without a victory under Diego Simeone, and they have not even scored in the previous three. Only once in their history have they gone four league derbies without a goal.
Madrid are also the only team to play a league match at the Wanda Metropolitano without ever losing (one win, two draws), with Simeone having won only 12.5 per cent of league games against opposite number Zinedine Zidane, his worst return against any coach from at least four meetings.
But Suarez has happy memories of facing Los Blancos. Although he's gone two games without scoring against them, his goal record overall reads nine scored in 12 league appearances versus Madrid, the most of any player since his first season in Spain in 2014-15.
What's more, he has an all-important side-kick back in form.
JOAO, THAT'S IMPRESSIVE
Joao Felix's sublime strike against Villarreal secured a valuable three points for Atleti last time out and ended his own month-long goal drought. He responded with a stony-faced 'shushing' celebration, to which a delighted Simeone responded: "I love it when players rebel."
Simeone will be desperate to see his €126m man in a similar mood come Sunday. Not only is he Atleti's most exciting individual talent, but he's also the man who has brought the best out of Suarez this season.
Joao Felix has created eight chances for Suarez in LaLiga in 2020-21, more than any other Atleti player. Of his four assists, three have been for the former Ajax man; only Marcos Llorente has provided as many for Atleti's number nine.
Perhaps Suarez has found a kindred spirit in Joao Felix: supremely talented, decisive, and "rebellious". What better double act to deploy in the Atleti's most important LaLiga derby in seven years?