Petr Cech was left relieved after Arsenal escaped from a "tricky" match against Premier League title rivals with a dramatic 2-1 victory.
Danny Welbeck came off the bench to glance home an injury-time winner after Theo Walcott had equalised Jamie Vardy's first-half penalty at Emirates Stadium on Sunday.
The game's turning point was a red card for Leicester's right-back Danny Simpson after 54 minutes, when his side led 1-0.
Speaking to BBC Sport, Arsenal goalkeeper Cech said: "We had to concentrate in the final stages because any counter-attack was becoming more and more dangerous as we searched for the winner.
"It was tricky. What I like about our win is that it is always tricky when opponents are down to 10 men.
"They have good organisation and are fighting for their lives. We managed to break them down and create chances.
"We kept missing chances but kept composure and kept coming. We had so many half-chances where we could have scored more."
Arsenal's win leaves them just two points behind league leaders Leicester.
"If you have a cushion of five or eight points, it is a big difference," Cech added.
"We overturned eight points to two - it is significant difference."