"We had a good win against the Dragons two weeks ago but if we don't turn up against the Ulster this Saturday then that's all forgotten about really.
"Sometimes the results can be quite frustrating, we've had two good performances against both Leinster and Muster at home this season and we didn't come away with a win.
"Against Leinster we outscored them two tries to none and still didn't come away with the win, but there has been less than a score in both matches which shows how close we've been."
With much talk about Ireland's summer tour to New Zealand and the competition for places that accompanies it, the interprovincial ties are a good testing ground for the national coaches to cast their eye over the contenders.
Bu purely focused on Connacht at present, McCarthy admitted: "You can't look too much into it and you try not to change anything just because it's an interpro.
"You just go out every game and put in the best performance you personally can do, it doesn't really matter who you are playing against, you just go out and try and be the best you can be in every match and hope that these things look after themselves."
Match-ups such as Brett Wilkinson and Ronan Loughney opposite Tom Court in the front row, Dan Tuohy against McCarthy in the second row and John Muldoon versus Chris Henry in the back row.
Furthermore out in the backs there should be fierce competition with Tiernan O'Halloran, Eoin Griffin, David McSharry and captain Gavin Duffy all holding their hands up for selection against the quartet of Andrew Trimble, Ian Whitten, Darren Cave and Craig Gilroy.
Last season's Connacht-Ulster clash at the Sportsground ended in a draw, but this season Ulster will have to contend with the newly refurbished stadium and the vocal Clan Terrace roaring on the home side.
Asked about the effect that has on the Connacht players, McCarthy said: "The atmosphere at the Sportsground, especially the Clan Terrace, has been unbelievable all season.
"The crowds have been great. It has made a big difference for us on the pitch, it really helps massively and gives you a huge boost when you hear the roars.
"This will be a massive test for us, Ulster are flying high, they had a well deserved victory in the Heineken Cup last weekend, they're going well on both fronts, in the Heineken Cup and PRO12.
"But you always want to test yourself against the best teams so even though it will be a tough game, it's one were really looking forward to."