Atletico Madrid proved last season that with an inspirational coach, a group of committed players and an enthusiastic support, it is possible to get the better of wealthy Real Madrid and Barcelona in La Liga.
Sevilla and Valencia, both sporadically able to keep pace with Real and Barca domestically in the past, have made solid starts to the season under Unai Emery and Nuno Espirito Santo respectively, raising hopes among their long-suffering fans that a genuine title challenge is possible.
If they are to maintain that challenge through to the end of the campaign, they must start making a habit of winning tricky away games like those they face on Sunday.
After nine matches, Europa League champions Sevilla are level with Barca on 22 points at the top ahead of their game at Athletic Bilbao, while Valencia, two points behind in fourth, play at Villarreal.
Sevilla warmed up for the trip to the Basque Country with a thumping 6-1 win at second-division Sabadell in Wednesday`s King`s Cup last-32, first leg.
Colombia forward Carlos Bacca has been the Andalusian club`s leading scorer in La Liga with seven goals but Emery used the Cup game to give some of his second-choice players a run out.
Iago Aspas, who is on loan from Liverpool after an unsuccessful stint in England, scored his first professional hat-trick, while another former Premier League recruit who has struggled to fulfil his potential, Jose Antonio Reyes, netted a long-range stunner.
"I haven`t been able to show all the football I have inside me," Aspas, clutching a match ball, told reporters.
"I wasn`t in good physical shape when I came here but I have to keep fighting and make things difficult for the coach," added the 27-year-old.
Valencia last won La Liga in 2004, having reached the final of the Champions League in 2000 and 2001, and hopes of reviving past glories have been boosted by the imminent takeover of the club by Singapore billionaire Peter Lim.
Lim was at the Mestalla to see last weekend`s 3-1 win against Elche and will become the debt-ridden club`s new majority owner once the remaining regulatory issues have been dealt with.
Coach Nuno has an exciting young squad, including, up front, recent Spain recruit Paco Alcacer and Alvaro Negredo, on loan from Manchester City and recently back from injury.
Teenage fullback Jose Luis Gaya, a product of the club`s own academy and a Spain international at youth level, has been one of the revelations of the season.
He warned his team mates to be focused from the start at Villarreal and to avoid the lapses in concentration that led to a 3-0 defeat at promoted Deportivo La Coruna`s Riazor stadium in their last away match on Oct. 19.
"Villarreal really like to keep the ball and we have to get after them immediately from the kickoff," Gaya told a news conference on Wednesday.
"If we come out half asleep like we did at the Riazor they will come after us and we have to start the game well," added the 19-year-old.
Barca will be looking to bounce back from last weekend`s 3-1 `Clasico` defeat at Real when they host Celta Vigo, where coach Luis Enrique was in charge last season, on Saturday.
Real, who have 21 points in third, play at Granada and Atletico, who are level on 20 points with Valencia in fifth, host Cordoba on Saturday.