Madrid - Atletico Madrid have four games in the coming weeks that are likely to determine whether they have truly joined Spain's elite or are in danger of slipping back in the second rank behind powerhouses Real Madrid and Barcelona.
Diego Simeone's Spanish champions play at Sevilla on Sunday and host Valencia the following week in La Liga, two sides who are keen to show they can also challenge wealthy Real and Barca on a more consistent basis.
A trip to Espanyol on March 14 is followed three days later by the Champions League last 16, second leg at home to Bayer Leverkusen, when Atletico will need to overturn a 1-0 deficit to the Bundesliga side.
Their chances have been hurt by Tiago's red card in Wednesday's first leg and the Portugal midfielder will be suspended for the return along with centre back Diego Godin.
Fullback Guilherme Siqueira and midfielder Saul Niguez picked up injuries in Leverkusen that look like sidelining them for several weeks and they join playmaker Koke, who has had a crucial role in Atletico's success in recent seasons, in the treatment room.
Simeone insisted after the defeat in Europe his squad has enough depth to cope with injuries and suspensions.
However, without Koke the team has lacked a creative inspiration in the centre and Arda Turan, who provides the same kind of spark from a more advanced position, has also been hampered by injuries in recent weeks.
Another worry for Simeone will be the way Atletico, who under the Argentine have won plaudits for their intensity and commitment, were outmuscled by Leverkusen at the BayArena.
Atletico looked a shadow of the formidable side which has beaten Real four times and drawn twice in six meetings in all competitions this season, including this month's historic 4-0 drubbing of their neighbours at the Calderon in La Liga.
"It was a very, very tough game," Atletico captain Gabi said in an interview with Spanish television after the Leverkusen game.
"Bayer played a very, very intense match, with a lot of speed up front," he added.
"They were enjoying pressuring us and they were superior in that sense but we still have the return leg and we will try to turn it around."
Atletico, who came within seconds of beating Real in last season's Champions League final, are third in the La Liga standings with 14 games left, three points behind second-placed Barcelona and seven adrift of leaders Real.
At this stage of the campaign, any more dropped points would surely mean the end of the bid for a second consecutive Spanish league title after their first in 18 years in 2013-14.