Second-half tries from Argentinian wingers Juan Imhoff and Gonzalo Camacho were enough to see off a Welsh side who suffered two key injuries.
Jamie Roberts and Alun Wyn Jones were both forced from the field as Wales’ only points came from the boot of full-back Leigh Halfpenny.
Here’s what Howley had to say on the defeat.
“International rugby is about doing the basics and in areas of attack and defence today we weren’t as efficient as we should have been.
“Losing Jamie Roberts and Alun Wyn throughout the game didn’t help but you have to cope with those changes.
“We struggled early on in the first-half with territory and possession. They dominated as they have done when we’ve played them in the past with possession and we defended particularly well in the first-half. When the game went to 12-6 we thought in the next 25 or 30 minutes we would kick on but Argentina showed great resilience to come back and took their tries particularly well.
“It’s disappointing. We spoke about pace and intensity throughout the week and we struggled in the latter half of the game. I said to the players it’s a test of character for everyone, coaches and management and we have to come back stronger.
“We’ve got three games to go, a hugely physical challenge with Samoa next week so it’s important we get back on the training paddock and sort things out.
“International rugby is about scoring tries. It hasn’t been a problem for us in the recent past but today as I say, we struggled with possession and territory.
“That was an area of concern in terms of struggling with territory and possession and not being able to put Argentina under the pressure we wanted them to, particularly in their 22 metre area.
“We have to work hard and be smart and there were areas today where we weren’t smart. We have to improve all round.
“I thought our scrum started off particularly well and we got a platform but we didn’t have the right attack in the right areas of the field. The territorial dominance was a bit disappointing today and that’s an area we need to work on to put teams under pressure.
“We trained well all week. We spoke about the tempo and the pace of the game which is important when you play Argentina and we just didn’t start well. That’s something we need to speak about as coaches and players ahead of another physical challenge against Samoa.
“Injuries are a part of rugby. We had injuries coming into this game and we’ve picked probably two or three more. Whether there’ll be available for next week we’ll have to wait and see on medical opinion but that’s the nature of the game.
“With injuries it gives an opportunity to others. Losing Jamie and Alun Wyn didn’t help, they’re two key members of our team but players came on and had a positive impact. We’ll have to sit down and see where we are next week.”