With Rees establishing himself as first-choice hooker in recent seasons, Bennett has had to cut a frustrated figure on the bench, starting just six Tests since March 2008.
But the loss of Rees due to the need for surgery on a persistent neck injury means the Ospreys forward is potentially in line to be first choice when Wales start their World Cup campaign against South Africa in Wellington.
Bennett started Wales' first warm-up game against England at Twickenham, and then made a positive impact off the bench in Saturday's reverse fixture at the Millennium Stadium.
But the 28-year-old knows he cannot rest on his laurels with regional colleague Richard Hibbard, Lloyd Burns and Ken Owens all pushing for a place.
He said: "It's a funny time selection wise, in terms of the coaches wanting to play certain formations.
"I was pleased to start at Twickenham and I was glad with how it went, we were disappointed to lose but we put in a great effort and played some good rugby.
"In the last game I was on the bench and when you have that you want to come on and do as much as you can.
"There is one more (warm-up) game to run and it's the same again. Whether I am starting or on the bench I need to come on, look to impress and make an impact in the team."
Although Bennett stands to gain from Rees' injury heartache, he readily acknowledges Wales will miss their leader when the serious business starts in the land of the long white cloud, although he expects senior players to fill the breach.
He said: "It's devastating news for Matthew, it's kind of been on the cards. I'm sure he is gutted to have to choose this route but you have to put your health to the foremost.
"When you lose a captain in any sport you are taking a big cog in how things run. But (stand-in captain) Sam Warburton has done well and there are other guys to step in.
"There is a good camaraderie in the squad and Matthew gets on with everyone and has a good influence which will be sadly missed, but there are plenty of senior players who can step up."
While Bennett showed up strongly after replacing Lloyd Burns in the weekend's 19-9 win over Martin Johnson's side, Wales will realise they have plenty of work to do at the set-piece.
The line-out, so often an issue in recent seasons, was again shaky while the Welsh scrum found itself under severe pressure from their English counterparts.
Wales will face a stern test in that area against Argentina on Saturday, as well as in that World Cup opener against the Springboks.
Bennett said of the line-out: "It only takes little things for a line-out to go wrong and it's just a couple of mistakes.
"The odd little lift, an overthrow or the timing and that had a bounce on effect and it kept occurring, it's something we need to rectify in training as there is no room for that kind of error."
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