The Argentine's first-half penalty proved to be the difference as Tony Mowbray's side surprised second-placed Cardiff at the Riverside on Saturday.
So far this season, the Teessiders have failed to string more than two successive wins together form which has left them floating in and around the relegation zone.
But with Saturday's win lifting them out of the bottom three on goal difference, Mowbray's side must now look to build on the win against Cardiff when they travel to the Keepmoat Stadium on Friday night to face Doncaster Rovers.
Arca is confident Boro have shown enough quality and have the fitness and work-rate to turn things around, and with games coming up thick and fast, the versatile midfielder believes the festive period is an ideal time to put some wins together.
It was an important win,
Arca said. It was a great three points and we have to take it into the Doncaster game next Friday and get something there.
We worked very hard we all worked for each other.
It's a good boost for the lads and we need to climb the table now.
Hopefully we can turn things around. We showed against Cardiff that the quality is there. The workrate and fitness are there, we just need to be consistent.
We've played really well in some games. We've been up and down but we need to have a good run now.
Christmas is coming up and there are a lot of games, and we need to take as much as we can from them.
Staggeringly, Arca's 40th minute penalty was his first league goal for Boro since September 2007, when he scored in a 2-2 draw with Sunderland.
So it was a surprise to everyone when the former Sunderland man placed the ball on the penalty spot.
But he kept his cool when others might not have done so and sent David Marshall the wrong way.
Arca admitted it was nice to score a league goal after such a long time, but insisted the three points were far more important than his personal joy.
After the game, he revealed why he had taken the ball out of Gary O'Neil's hands and admitted he was relieved to see the ball hit the back of the net.
It's a long time since I scored and it's always good to score, Arca said.
But at the moment it doesn't matter who scores the goals, it's just important to get the win.
I was quite far away from it (penalty incident) but it looked a foul to me. It could have been a red card.
I don't know how far away the other centre-back was. It doesn't really matter to us, we got the penalty and that was the important thing for us.
I'm not normally the penalty taker, it just happened.
Gary O'Neil had the ball and I asked him for it. He asked if I was going to score, I just said I hope so!' We had a laugh about it after the game, but I just felt confident of taking it. I'm too soft and have always let other players take them but I just went for it this time and luckily enough it went in and won us the game.