Atletico Madrid striker Jackson Martinez is frustrated after a disappointing start to his career in Spain but the Colombia striker is determined to work hard to end his relative goal drought.
Martinez, who joined from Porto in the close season, has managed just one goal this term and drew another blank on Wednesday as Atletico surrendered the lead and were beaten 2-1 at home to Benfica in Champions League Group C.
Martinez was brought in as a replacement for Croatia forward Mario Mandzukic, who was sold to Juventus, but has yet to reproduce his form from the Portuguese league, where he was top scorer in each of his three seasons with Porto.
If selected for Sunday's La Liga derby at home to Real Madrid, the 28-year-old will have another chance to show Atletico fans what he is capable of.
"It's frustrating because you feel the support of the fans, your team mates and the staff and you want to give your all so that things go well," Martinez told Spanish television.
"Things are not going as I would like but I will keep working so that in the next game, the derby, I can improve."
Atletico coach Diego Simeone did not appear too concerned by Wednesday's reverse, which left the 2014 runners-up in second place in the section on three points from two matches, with Benfica leading on a maximum six.
Astana and Galatasaray each have one point after they drew 2-2 in Kazakhstan on Wednesday.
"Right now it's understandable that the team is unhappy with the defeat they suffered," Simeone told a news conference.
"We have to face a very important game (on Sunday)," added the Argentine. "I don't think there will be any need to motivate the players for a match like this one."
Atletico, the 2013-14 La Liga champions, are fifth in Spain's top flight with 12 points from six matches after they were beaten 1-0 at surprise leaders Villarreal last weekend.
(For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)