Rafael feels one of the fixes required to get Manchester United back on track is to stop losing goals at set-pieces following the 2-1 defeat at Sunderland on Tuesday night.
Ryan Giggs unluckily got the final touch when Wes Brown met a free-kick at the far post in first-half stoppage time to put through his own net and hand the Black Cats the advantage. Although Nemanja Vidic equalised in the Capital One Cup semi-final first leg, Tom Cleverley's challenge on Adam Johnson enabled Fabio Borini to claim the winner from the spot.
Rafael, making a welcome return after being injured at Hull City on Boxing Day, was clearly upset with the penalty award and was booked for voicing his frustration. However, the right-back is merely concentrating on ensuring the Reds improve in defence.
The Brazilian told ManUtd.com: "We conceded two goals - one was from a free-kick and another one was a penalty. I think, when we stop conceding these type of goals, we can improve. So we just need to fix this.
"Now we need to focus on the Swansea game in the league at the weekend and forget this [Sunderland] match. But we really want to get to Wembley. We still have a big chance at Old Trafford in the second leg."