Northern Ireland manager Michael O'Neill believes poor finishing led to the 2-0 defeat by Israel in Belfast.
O'Neill's side failed to take their chances before Lior Refaelov and Eden Ben Basat gave the visitors a World Cup qualifier victory at Windsor Park.
"The key is when you are on top in games you must capitalise on the chances you get," said O'Neill.
"In the first half we created chances but didn't take them, so we make life very difficult for ourselves."
He added: "We got caught cold again on the counter-attack on two occasions - ultimately we have lost a game where we should never have lost."
Northern Ireland hopes of qualifying for next year's World Cup in Brazil are fading fast with just three points taken from five matches.
The torment continues for O'Neill, who has gone nine games without a victory since taking over from Nigel Worthington.
Northern Ireland have scored only three goals in their five qualifiers, a sign that they have been struggling in attack.
O'Neill added: "I thought we were excellent in the first half and we had some really good possession.
"But we didn't play as well in the second half and we got bogged down a bit."
The defeat against Israel came after three successive 1-1 draws - with a point in Portugal coming in between identical results at home to Luxembourg and Azerbaijan.
O'Neill said: "There's been a pattern with us dominating sections of games - we've been in strong positions in our three home games in qualifiers but not capitalised.
"At this moment in time we are finding it difficult to win games. The mental side of the game to get that little bit extra to win matches at this level - it is just not there at this minute in time.
"However, we just have to persevere, work hard and change it."