Arsenal goalkeeper David Ospina has told IBTimes UK he is enjoying a "healthy battle" with Wojciech Szczęsny for the 'keeper's jersey after conceding two goals during the 2-1 defeat against Tottenham on Saturday 7 February.
Manager Arsene Wenger recently said the Polish international goalkeeper was still his first choice even though the Colombia international has been the starter since Szczęsny reportedly smoked in the showers following the New Year's Day loss at Southampton.
Having moved to the Emirates Stadium last summer for around £3m, following an impressive World Cup, Ospina took the opportunity to prove his worth with three Premier League clean sheets in the victories over Stoke City, Manchester City and Aston Villa.
However, the 26-year-old 'keeper was unable to extend the run during the north London derby after Harry Kane scored a brace in the second half to cancelled Mesut Ozil's opener and give Tottenham the three points.
Questioned after the game whether he already feels like Arsenal's number one, Ospina said: "This is an everyday battle.
"I have to keep proving myself in every game and unfortunately [against Tottenham] I couldn't secure a clean sheet. But I have to keep working. There is a very healthy competition [with Szczęsny] and we have to be at 100% [to keep the role].
"I have to keep working in every game and in every training session to keep taking advantage of the opportunity."
Meanwhile the Colombian star expressed his frustration at the defeat in such a "special game".
"We are sad because it is a very special game. It was the derby but now we needs to look ahead to the next game against Leicester," Ospina said.
"Tottenham did the right things. They pressed well and scored two goals to overcome the result. We tried to play our game but they got the victory."
Arsenal led Spurs to control the possession while they tried to made the difference with counter-attacking football.
Asked about whether Wenger demanded them to play like that, Ospina said: "We knew Tottenham were going to control the game because they played at home.
"We tried to control their [attacks] and scored an early goal but unfortunately we couldn't secure the victory.
"It is true we had not many chances but we are not worried because we have been playing well lately. Now it is just time to look ahead."