Madrid, who last season ended Barcelona's three-year dominance in La Liga with a record-breaking campaign, were held 1-1 by Valencia at the Bernabeu last Sunday despite taking a 10th-minute lead through Gonzalo Higuain.
The disappointment of that home draw was then compounded by arch rivals Barca - who Madrid meet in the first leg of the Spanish Supercopa tonight - later winning their opening fixture 5-1 against Real Sociedad.
Jose Mourinho's men now face a potentially tricky trip to local rivals Getafe, and Lacen believes his side are more than capable of causing an upset having last season beaten the likes of Barca, Valencia, Sevilla and Atletico Madrid at the Coliseum Alfonso Perez.
"Last year we won here against a lot of big teams and we want to continue like that. I have very good feelings about the game against Madrid. It will be difficult but hopefully we can get the three points," he said in AS.
"We have a team to be at the top and we've started without injuries. This will help us."
The Algeria international, whose side lost their opening fixture 2-1 at Sevilla, is not expecting it to be easy though, adding: "They will be more dangerous. They dropped points at home and they will come here with the attitude that they cannot lose any more."
Barca also have a difficult-looking away trip this weekend as they travel to Osasuna.
The Catalan giants thrashed Osasuna 8-0 at the Nou Camp last September but were then beaten 3-2 at the Estadio Reyno de Navarra in the return meeting in February.
Like Getafe, Osasuna also started this season with a defeat after going down 2-0 at promoted Deportivo La Coruna and winger Sisi knows they will need to do better to get anything against Tito Vilanova's men.
"We have to look at what we did badly (against Depor). Work day by day knowing that our next opponent is Barca and that we need to have a good game if we want to win," he said.
Depor's hopes for the season will face a stern examination when they travel to a Valencia side that have finished third in the last three seasons and gained that morale-boosting draw at the Bernabeu.
There is a repeat of May's Europa League final at the Vicente Calderon on Monday night where Atletico Madrid play host to an Athletic Bilbao side facing plenty of problems at the start of the campaign.
Athletic, who lost 3-0 to Atletico in that final, are facing the prospect of losing star duo Fernando Llorente and Javi Martinez before the close of the transfer window, while they were humbled 5-3 at home by Real Betis in their opening league match.
Elsewhere, Malaga and Real Mallorca will be looking to build on opening-weekend victories when they meet at La Rosaleda.
Pellegrini expects a tough test from Mallorca, who got their own season under way with a 2-1 home victory over Espanyol last weekend.
"I do study our opponents," Pellegrini said.
"We'll be trying to impose our style of play in the match tomorrow, though Joaquin Caparros' team has a lot of character on the pitch.
"Mallorca are a good team with some good players, who are continuing their impressive performance from last season (when they finished eighth), which is why they are as tough a team to beat now as they were then.
"But if we play well, we'll get the three points."
Meanwhile Betis host Rayo Vallecano in another match involving sides boasting winning starts.
Sociedad and Celta Vigo both go in search of their first points when they clash on Saturday, and it is the same story at Estadi Cornella-El Prat where Espanyol take on Real Zaragoza.
Also, Sevilla go to Andalusian rivals Granada and promoted Real Valladolid take on Levante in Monday's other fixture.
Saturday's La Liga Fixtures
Sunday's La Liga Fixtures
Monday's La Liga Fixtures
Valladolid vs Levante
Atletico Madrid vs Athletic Bilbao