Three points clear at the top of La Liga, a shrewd-looking signing in the bag and soaring optimism among their fans, Atletico Madrid are on could nine ahead of Wednesday's King's Cup semi-final clash against Real.
One of Spanish soccer's poorer relations, under inspirational coach Diego Simeone, Atletico are mounting a genuine challenge this term to bitter city rivals Real and Barcelona, the world's two richest clubs by income.
A former Argentina midfielder who played for Atletico when they won a La Liga and Cup double in 1996, Simeone has moulded his unpretentious but talented and hard-working squad into a formidable unit.
They were further boosted on Friday by the return of Diego on loan until the end of the season.
The Brazilian playmaker helped Atletico win the Europa League in 2012 during another loan stint and came off the bench to score in Sunday's 4-0 league win at home to Real Sociedad.
The thumping victory on an emotional night for the Atletico faithful, who paid tribute to club great and former Spain coach Luis Aragones before kickoff following his death at the weekend, put them three clear of Barca after the champions were beaten at home to Valencia on Saturday.
Real also slipped up and were held to a 1-1 draw at Athletic Bilbao on Sunday when top scorer Cristiano Ronaldo was sent off after clashing with Carlos Gurpegui and Ander Iturraspe.
The stage is set for Atletico to inflict more Cup pain on their detested neighbours, who they beat 2-1 in last year's final held at Real's own Bernabeu stadium.
It was the first time they had got the better of Real in 14 years in any competition and they built on that success with a 1-0 La Liga win, again at the Bernabeu, at the end of September.
"We have the players to compete," Simeone told a news conference after the Sociedad game.
"Diego's arrival will give us what you saw tonight," added the 43-year-old.
"A player with attacking ability, personality, aggression in his play. Whenever he gets the ball dangerous things can happen."
One of the doubts surrounding Atletico was that possibly they did not have enough depth in their squad to challenge on three fronts.
They are also through to the last 16 of the Champions League, where they will play struggling Italian side AC Milan.
However, the capture of Diego as well as the recovery from injury of defensive midfielder Mario Suarez have come at just the right time and will allow Simeone more freedom to rotate his players and keep them fresher.
Real, meanwhile, will be seething after losing ground on Atletico and squandering a chance to climb above Barcelona into second on Sunday.
Barca lost at Bilbao's new San Mames stadium in La Liga in December and Real also struggled to cope with the intensity of the Basque club's players.
Ronaldo should be available to face Atletico in the Cup as he will serve the suspension that comes with his red card in La Liga, while coach Carlo Ancelotti also hopes to have record signing Gareth Bale back from injury.
On the other side of the draw, record winners Barca host Sociedad on Wednesday after suffering their first home defeat of the season against Valencia.
Despite their setback at the Nou Camp, where they had won 25 straight La Liga matches stretching back to last season, they should have too much for the Basques, who lost to Barca in the 1988 final on their last appearance in the title decider.
Argentina forward Lionel Messi netted Barca's second from the penalty spot on Saturday as he continues to get back into his stride after a two-month injury absence, the latest in a series of muscle problems.
"I have played a few games now and I am in good shape psychologically," Messi said at a promotional event on Sunday.
"I was down when I had one injury after the other and today that is all forgotten," the four-times World Player of the Year added.
The return legs are the following week and the final is on April 19 at a yet-to-be-determined venue.