BARCELONA: Rafa Benitez held on to his job last year but faces another tough test of his coaching credentials on Sunday when Real Madrid visits Valencia for its first Spanish league game of 2016. Benitez has been the focus of criticism from disgruntled fans for Madrid's unpredictable campaign, which has included a lopsided loss to fierce rival Barcelona and its embarrassing disqualification from the Copa del Rey for fielding an ineligible player. Madrid travels to Mestalla Stadium after two easy victories at its own Santiago Bernabeu home that failed to win over its most skeptical supporters, some of whom jeered Benitez. Madrid defender Pepe has called for calm. 'We have to let our coach continue to improve,' Pepe said. 'If a new manager came, we'd have to adapt to new systems and that isn't good. We should save the evaluations for the end of the season.' Madrid has struggled on the road this season, dropping points on four of eight of its outings. Its last away game ended in a 1-0 loss at Villarreal. Madrid is in third place, two points behind Barcelona and Atletico Madrid. Defending champion Barcelona has played one less game than its rivals. Here are some more things to know about the 18th round of La Liga: ALSO IN NEED Benitez's counterpart on Sunday is also in need of a victory. Former Manchester United defender Gary Neville's coaching debut has got off to an uninspiring start. Valencia has only beaten a third-division side in the Copa del Rey since he took over. Otherwise, the team has recorded a pair of draws and two losses, including a poor showing in a 1-0 league defeat at regional rival Villarreal on Thursday. That loss left Valencia 10th and 11 points from the Champions League spots. 'The team is united and we are trying to get a win as soon as possible,' said Valencia striker Alvaro Negredo. 'January will be a key month.' BARCELONA DERBY Barcelona makes the short trip across the Catalan capital to play the first of three derbies against Espanyol on Saturday. The two clubs will also meet in the round of 16 of the Copa del Rey over the next two weeks. Barcelona will be heavily favored to continue its record form of 2015, when Luis Enrique's team won five titles and set a new record 180 for goals scored. The strike trio of Lionel Messi, Neymar and Luis Suarez combined for 137 of those goals. Suarez is leading the league this campaign with 15, followed by Neymar and Madrid's Cristiano Ronaldo with 14 each. Espanyol's defense is the fourth worst in the competition with 28 goals conceded. Only the three teams in the relegation zone have conceded more. BEFORE THE STORM Atletico Madrid hosts last-place Levante on Saturday before facing a difficult run of matches in the rest of January. Diego Simeone's team then plays at Celta Vigo and Las Palmas, returns home against Sevilla, and finishes the month at Barcelona's Camp Nou. Levante has lost four of its last five, scoring just two goals in that stretch, while Atletico has the best defense in the league with only eight goals conceded. SURPRISE CLASH Other than Madrid at Valencia, the most intriguing fixture of the round promises to be Deportivo La Coruna hosting Villarreal on Sunday. Villarreal heads to Riazor on the strength of four consecutive wins that have pushed it into fourth place. Deportivo, meanwhile, is the surprise side of the season. Led by striker Lucas Perez and his 12 goals, it is in sixth place after not losing in eight rounds. On Saturday, fifth-place Celta plays at a resurgent Malaga that has won three straight.