The Blues were on course for their first victory of the Championship season until the Hornets grabbed an equaliser deep into stoppage-time to stun Portman Road.
It means the Suffolk side have now failed to win in 13 Championship games, heading into Saturday's crunch match at second-from-bottom Plymouth.
Keane said: "Watford rode their luck and we were let down by bad finishing and good goalkeeping.
"But I've been in football long enough to know that if you don't take your chances it'll kick you in the teeth.
"We're not scoring enough goals. I can sit here and make excuses but we've got to take our chances.
"Tonight we didn't but I've got no problem with my team's performance, in terms of their spirit and work-rate.
"We got the ball in the right areas and created chances, but when you don't get a second goal there are bound to be a few nerves.
"Thirteen games without a win is a bad run. We can't get away from that and there's no hiding place.
"I can't fault my players and back them 100 per cent, but to go that many games without a victory is unacceptable."
After taking an early lead, rather than falling behind, as has become the norm, Town gave themselves the best possible platform.
It was a very well-worked goal, started by the influential Liam Rosenior. His long free-kick was met by Jon Walters, who crept behind the defence and headed the ball back across goal for Gareth McAuley to bury a close-range header.
Town had a succession of chances but, despite being on top, a second goal proved elusive and there were more than a few jitters as the game entered its latter stages, especially given the costly late goals they have conceded against the likes of Doncaster, Sheffield United and Barnsley.
Those fears were then justified deep into injury-time when Nathan Ellington prodded home a cross by Danny Graham.
Hornets boss Malky Mackay said: "Ipswich deserved to win. We were below par and most definitely got out of jail. If I'm honest, I couldn't see a goal coming.
"We kept going and going and were still fighting, which I expect, but it didn't look like we would create an equaliser.
"But when there are five or 10 minutes left in any game you've always got a chance - you've just got to keep pushing.
"It was great we got the goal and a point and we showed a real resilience and never-say-die attitude.
"This is a tough league and it's a real scrap and battle. A lot of teams are showing real resilience and I'm glad it was us tonight."