His days as an attacker are a distant memory, but he's been very solid defensively when played there. Bolasie is a tricky player, and he didn't give him a sniff. Seems to win every one on one and every physical battle.
I prefer Rafael every day of the week, but I have no problem with Valencia standing in, from a defensive point of view.
I disagree with the notion that he's a good defender, Smalling got sent off literally last week, trying to bail him out from bad positioning. He doesn't really have defensive instincts and is prone to switching off. He had a bit of spell last season where he was costing us goals at RB, off the top of my head vs Chelsea away and vs Everton home. He's also a bit too rash in the tackle and gives away too many free kicks coming through the back of players.
To be fair, full back is one of the hardest positions on the pitch to get the positioning spot on, and you can't really blame him since he's only played there part time. He was good today defensively, mainly because Bolasie tried to run/outmuscle him, and you can't out-Valencia our Tony. But when he comes up against cuter movement, overlapping full backs etc, it's a different story.
Going forward he is still frustrating. As crap as Januzaj was today, he wasn't helped by the fact that Valencia didn't make a single overlapping run. He's clearly got some serious confidence issues, because he can go past players with ease around the halfway line but when it comes to taking on his man in the final third he is awful, and has been awful for almost three years.
Rafael is better both going forward and defensively - who would have thought that in 2012.