O'Shea disliked the Blue Bombers performance in a 26-3 to the Edmonton Eskimos on Thursday in front of Winnipeg's largest home crowd of the season.
"The biggest disappointment, besides teammates thinking they let down teammates, is having a crowd like that and putting that kind of effort forward," said O'Shea, as the Bombers fell to 3-1.
The crowd at Investors Group Field topped 30,000 for the first time this season with 30,976 in attendance to watch the Eskimos claim sole possession of first place in the CFL West at 4-0.
A scrambling Mike Reilly may have been the difference maker. He rushed for a team leading 96 yards in a game where defences on both sides were making life hard for offences.
"It was a long night for both offences, I think," said the Eskimos quarterback, sacked four times to five for Winnipeg's Drew Willy.
Reilly was held to one offensive touchdown, with another scored by the defence and the rest of Edmonton's points coming from Grant Shaw field goals. Winnipeg had only one field goal from Liram Hajrullahu and he hit a post on another try.
"Both those defences are really good," said Reilly. "Even in the first half we had some good drives that we didn't finish off. So, certainly, we like to come away with touchdowns rather than field goals but the way our defence is playing right now, it's enough to get the win."
Slotback Fred Stamps, one of the team's best and most consistent receivers, was injured in the game and coach Chris Jones said later he was still being evaluated.
"It was a physical night for both sides and again our quarterback got tested a time too many (but) again he's a physical big quarterback and that's what he does, he's a winner," said Jones.
"They were 3-0 for a reason. They're a good football team and they've got great schemes and things of that nature and we had to go out and earn that win."
O'Shea said the way Reilly slipped tackles time and time again showed the Bombers his power, something they knew he had worked on in the off-season.
"Yeah he's strong and tough," said O'Shea. "We underestimated him and give him that credit and when we look at the film we'll be disappointed we didn't squeeze a little harder and bring him down."
That said, the defence kept the Bombers in the game. Winnipeg's offence had the ball for just 21:34 to Edmonton's 38:26. But in the first and final quarters, when the Eskimos scored 20 of their points, the Bombers had the ball for less than seven of those minutes.
"We never got a rhythm going," said Willy. "We left our defence out there. They played really well. Anytime you don't possess the ball very much it's tough to put points on the board."
He was wearing an ice bag on his left ankle but said he wasn't hurt that badly and it won't affect his ability to play next week in B.C.
Edmonton's only touchdown in almost 50 minutes of football came from the defence on a first-quarter interception, carried in by former Bomber bad boy Odell Willis.
But despite some solid drives (Edmonton had 24 first downs to Winnipeg's 11) all the Eskimos offence could muster were field goals until the fourth quarter.
With Stamps injured, Reilly finally connected with A.J. Guyton with a 13-yard throw to make it 20-3 with about 10 minutes left, the first and only touchdown by the offence. He said Stamps would have drawn more coverage.
The Bomber offence had hardly touched the ball until Nic Grigsby gave them a first down with just over two minutes left in the second quarter.
Willy followed with a 50-yard throw to Clarence Denmark but he was sacked on the next play and Denmark couldn't hold it in the end zone on a touchdown try, forcing Winnipeg to settle for a field goal.
Notes: The last time an unbeaten Winnipeg and Edmonton tussled for first in the West early in the season was in 1961. Edmonton won that game but Winnipeg went on to win the Grey Cup. ... Zach Anderson had two of Winnipeg's four sacks and picked up what initially looked like a fumble deep in Edmonton turf on Thursday, although it was ruled down by contact. Willie Jefferson had two of Edmonton's four sacks. Regular punter Mike Renaud hurt himself during the warmup leaving Hajrullahu to handle punts as well.