Notre Dame gave one away last week and it hurt, both as an Irish fan, and in ND's quest to get into the national championship tournament.

The loss put ND at 4-1 and into a free-fall in the two national rankings, going from 6th to 15th. I think that fall was too much considering all the factors, but ND is not really liked by the national media.But the loss does not end ND's quest for a title.When Ohio State won the national title in 2014 the Buckeyes had one loss and were ranked 20th in the AP poll at the same point of the season as the Irish are this year. Ohio State regrouped, and continued to improve weekly resulting in a national title.So the quest is not over, but the Irish face some serious challenges ahead.Giving up the ball four times - three fumbles and one interception - was the biggest reason for the Irish defeat. You can't give the ball away that many times to an excellent football team like Clemson. The Tigers are too good to be given added opportunities.The second factor in the game that hurt the Irish was another slow start by the defense. The Irish defense didn't really get into the game until the second quarter and ND was down 14 by that time.The pluses in the game were that the defense, when it did wake up, played a solid game. Also, quarterback DeShone Kizer continued his improvement. Yes he had an interception late that looked like it doomed the Irish, but he recovered and led them to within two points of tying the game and sending it into overtime.Bottom line is a better turnover margin (minus-three for ND) and stronger defensive start could have resulted in a much different outcome.Kizer was the better of the two QBs. He threw for 321 yards against the nation's No. 3 defense against the pass, completing 19 of 34 with two TDs, including a one-yarder to Torii Hunter Jr. with 07 remaining that set up the second failed two-point conversion play in the fourth quarter for the Irish.Another bright spot was the 46-yard field goal by true freshman Justin Yoon. The Irish running attack was stalled by a fine defensive effort by Clemson in facing up to the big ND offensive line. Overall, it was a tough loss but now we will learn just how good ND is and if head coach Brian Kelly can get this team with so much potential focused Saturday against a very good Navy team.More on the Clemson game later.Navy comes into the game at 4-0 with wins over Colgate, 48-10; East Carolina, 45-21; UConn, 28-18; and last week Air Force, 33-11.Navy, of course, runs the triple-option offense and no team runs it better. Navy is 3rd in the country in rushing with 339.8 yards per game. And senior QB Keenan Reynolds is one of the best at running the option offense as he has run for 540 yards on 87 carries and has scored nine TDs so far this season. Backing him up in running back Chris Swain with 368 yards on 68 carries and four TDs. The top receiver is Jamis Tillman with six catches for 97 yards and a score.An added threat for the Navy is its defense. In the past Navy's defense didn't measure up to its offense and even though they scored a lot of points, they gave up a lot. Not this year. The Middies defense has allowed just one rushing touchdown this season and that came last week in the final quarter of the win over Air Force. Navy has more sacks than ND's defense and has forced more turnovers.ND leads the series, 75-12-1 and has won the last four, but all but one was a struggle. ND won last year, 49-39 while the last Navy win was in 2010, 35-17.The game will be televised nationally by NBC-TV with a 3:40 p.m. kickoff.IRISH NOTES: Some more game stats. To show how the ND rush game was shutdown C.J. Prosise finished with 50 yards on 15 carries, 100 yards below his average, but he had 100 yards pass receiving in the game. Freshman Josh Adams got just two yards on two carries. Kizer had 60 on 15 and a score. Receiving figures were just as bad. Will Fuller had two catches for 37 yards; Chris Brown four for 83 and Amir Carlise, three for 34. Jaylon Smith had seven tackles and Max Redfield 14. It's bad when a member of the secondary leads the defense in tackles. ... Kizer faced the No. 3 defense against the pass and still moved up in pass-efficiency standings this week. Kizer's 154.0 rating would be the highest qualifying mark for any one QB in the 12 seasons Kelly has coached at the FBS level. Kizer is also averaging 3.6 yards per carry, which is not bad. Kizer is ranked 22nd in the nation while Clemson's highly rated Deshaun Watson is 27th and former ND quarterback and Florida State starter, Everett Golson is 33rd …. The Clemson defensive effort in holding the potent Irish run game to just 116 yards had ND drop to 13th nationally in rush offense …. Prosise, who came into the game as the nation's fifth-leading rusher, dropped to 12th …. Kelly said he met with the team captains after the game and told them what is ahead and what they must do to reach their goal of playing in the national spotlight. He also warned them, one more loss would shatter any national title tournament hopes …. Senior Tyler Luatua, ND's best blocking tight end, has been cleared to play after missing the last two games due to a concussion ... This is the first time in the 88-game series between ND and Navy that the Middies will not be an independent. Navy is now a member of the American Athletic Conference ... Saturday is a "trap game" for the Irish. What I mean is ND is coming off a tough loss and faces archrival Southern California next week. The question is will the Irish come out flat Saturday or be thinking ahead to USC. Either way it could mean an upset win by Navy. ND cannot afford another loss and has to play Saturday like it's a bowl game. In my preseason picks I have the Irish winning Saturday. I think they will, but it won't be easy by any means.