The Robins were behind to a ninth minute Anthony Thomas strike at half time and despite an equaliser from Matty Day, were beaten by a 78th minute Kiemon Robinson winner.
Speaking to Football in Bracknell, Warner said: “After Tuesday night’s defeat I said to the players it’s disappointing but we created 20 chances, their goalkeeper made seven match winning saves, we had plenty of one v ones which we’d normally take advantage of and plenty of other chances.
“We just have to be positive and crack on.”
Warner pointed to an improvement in the Sarnies form in recent weeks that following the win over Bracknell, includes a win at Northwood and 1-1 draw with Bedfont Sports.
Warner said the defeat was still a shock but remained pragmatic. He said: “I’m still recovering from the shock on Tuesday. If we’d played five weeks ago we’d have been alright but they’ve picked up with results against Northwood and Bedfont. They’ve obviously improved.”
On the race for a play off spot, which Bracknell need just one more win to secure, the Robins boss said: “We just have to be positive, it’s still in our hands. Another defeat though and it might be a bit different!”
Bracknell remain odds on to finish runners up in the division this season and travel to Northwood on Saturday. The full list of Berkshire fixtures for Saturday is here.