Bayern Munich midfielder Xabi Alonso believes his side is well on course to achieve a place in the Champions League quarterfinals for the sixth year in a row.
Bayern, who eliminated the Gunners at this stage of the competition in 2012-13 and 2013-14, scored four goals in the second half to brush aside Arsenal at the Allianz Arena.
"We played very well, we executed our plan to perfection," Alonso told Cadena Ser radio. "We had expected more from the first half with the score at 1-1, but after the restart, we got the goals.
"We wanted to make life difficult for them and we did that. There are still 90 minutes but we have a great advantage heading into the return leg at the Emirates. A debacle would need to happen for us to be eliminated.
"We will nevertheless go to London with the same focus and preparation that we showed in this game."
Alonso also says Barcelona's surprise 4-0 defeat at Paris Saint-Germain is a warning to other teams that no game can be taken lightly.
"I didn't expect Barca to lose in that manner because they are used to competing at a high level and playing in big games," he said. "It was surprising. I think this Champions League is balanced.
"However, on any given bad day, you can experience what Barca went through [in Paris]. Obviously Real Madrid are strong and are still favorites to retain the title."
Real beat Napoli 3-1 at home on Wednesday in their Champions League last 16 tie.
Bayern reached the semifinals of the competition under former coach Pep Guardiola in the last three seasons and Alonso is confident the team can go far again.
"We have a different coach but the important thing is that we have the players," Alonso said. "The team is well built not just for this season but for the future."
Alonso, who has won the Champions League with Liverpool and Real Madrid, has yet to make a decision regarding his future.
The former Spain international has not signed a new contract with Bayern, the club he joined from Real in the summer of 2014, with his current deal ending this summer.
"I don't know what is going to happen, I haven't made a decision," he said. "Time will tell. I'm just enjoying myself and I'm focused on the season.
"There is no hurry. At this stage of my career, I'm not going to stress out."