Joao Felix's superb pass set up Koke's winner as Atletico Madrid jumped to third in La Liga on Saturday with a 1-0 win over Rayo Vallecano.
With Barcelona playing Real Madrid in the Clasico on Sunday, Atletico took advantage at Vallecas, their fifth consecutive victory giving them some breathing space in the fight for the top four, AFP said.
They had to see out the last nine minutes with 10 men after Angel Correa, on as a substitute, was sent off. But just as they did against Manchester United on Tuesday in the Champions League, Atletico dug in and held on.
They now have a five-point lead over Real Betis in fifth and sit three ahead of Barcelona in fourth, even if Betis have one game in hand and Barca two.
Diego Simeone's side certainly head into the international break with momentum for the run-in, after rounding off an excellent seven days that began with victory against Cadiz before knocking out United.
The draw on Friday ensured the reward for that result will be a meeting with Manchester City in the last eight and while Atletico will be clear underdogs against the reigning Premier League champions, they are also building form and confidence at just the right time.
"I think we have found the key, we have increased the intensity, the team is playing better and that's reflected in the results," said Koke.
"We have grown together," added Simeone.
Felix has been key, this his seventh goal or assist in his last seven matches, the 22-year-old repaying Simeone's faith while Luis Suarez again started on the bench.
This was the sixth consecutive game Suarez has been named as a substitute and, with the quicker, more agile pairing of Felix and Antoine Griezmann up front, Atletico have hit their stride.
Rayo stay 12th, after making it 10 league games without a victory. They were in contention for the European spots only a few weeks ago but now sit just eight points above the relegation places.
Felix was at the heart of the decisive moment in the 49th minute as Koke collected on the edge of the area and played inside to the Portuguese.
As Rayo's defence turned to Felix, nobody spotted Koke continuing his run, except the forward, who slid the ball through first time for Koke to curl in the finish.
Griezmann should have made it two but was denied by a close-range save from Stole Dimitrievski and Atletico were almost undone when Oscar Valentin's driven cross found Randy Nteka free five yards out. Somehow Nteka skewed over.
Correa was sent off in the 85th minute for what appeared to be an altercation with Rayo's Alejandro Catena and Rayo went close in injury-time, after Dimitrievski was sent up for a corner. The ball dropped loose for Ivan Balliu and he shot low, but straight at Jan Oblak.
