MADRID, Oct. 29 (Xinhua) -- Oviedo became the first La Liga side in Spain's Copa del Rey to lose to lower league opposition on Tuesday while Girona beat fifth tier Constancia after extra time.

Oviedo's 4-2 humiliation against Ourense should serve as a warning to the five top-flight teams in action on Thursday that if they fail to focus on the Copa, they could also end up falling by the wayside.

Levante is arguably the team most at risk of an upset with the side that returned to La Liga this season making the short trip to play Orihuela, a side that plays in the fourth-tier RFEF II and plays at the 7,000 Los Arcos Stadium.

Levante coach Julian Calero will probably rest top-scorer Etta Eyong, but will probably have him on the bench in case his pace and power are needed in the second half.

Espanyol will hope to celebrate the 125th anniversary of its foundation away to Atletic Lleida from the RFEF II division, but this is another match where the top-flight side will need to be careful.

Celta Vigo claimed its first win in La Liga on the weekend with a 3-2 success away to Osasuna and now travels to play the amateur side of Puerto de Vega, which plays in the sixth level of the Spanish football.

Puerto de Vega shouldn't be a problem for Celta, although with the club also playing Europa League, coach Claudio Giraldez will probably put the emphasis on those competitions ahead of the Copa.

The amateur club Getxo has had to move its match against Alaves from its Fadura Stadium to nearby Gobela, which is the home of third tier Arenas Club de Getxo, meaning Alaves will play on an artificial surface.

Betis will come face to face with a former player when it plays away to Palma del Rio, a sixth-tier side that has former Betis striker Sergio Leon in its ranks and plays its games in Sergio Leon Stadium, with temporary stands added to increase its capacity for Thursday's match.