Berkswell must win two of their last three matches to be certain of retaining their Birmingham Premier League status after a bittersweet bank holiday weekend.
On Saturday, they beat Wombourne, all 20 wickets falling for a total of 125 runs.
But on Monday, Berkswell came unstuck against Walmley, scraping their way to 200 all out.
Berkswell started well with the bowling but, with Chris Booth hitting 92 and Andrew Hendry 70 not out, Walmley won with seven overs to spare, closing on 204 for 7.
After the match, Ostler said: “Lucklily other results went our way but it is still tight at the bottom.”
It was a different story on Saturday as Ostler’s men had the better of a low-scoring contest.
Berkswell finished 73 all out but Wombourne made just 52.
Batting first, Berkswell were reeling at three for three by the second over.
Imran Arif was lbw for one off the first ball of the second over, Mohammed Akhlaq was caught behind off the fifth for a duck and Tom Lewis was also lbw without scoring off the last ball of the over from Steve Howard.
Skipper Dominic Ostler went for a first ball duck, caught at slip by Mark Gran off the first ball of Howard’s next over.
Opener James Neale and Jack Cornick added another 12 before Cornick was caught at mid-on by Dave Hemming in the eighth over for six.
With half the side out for 20, things looked perilous for Berkswell, but a partnership of 37 runs between Neale and Jon Coleman eased the nerves. Having batted cautiously on the difficult track Coleman, on 17, edged a ball from spinner Tom Brown to Ed Fisher behind the stumps, the wicket falling in the 19th over.
The Brown and Fisher combination had further success in Brown’s next over, claiming the wickets of Phil Neale and Chris Cheslin, both without scoring, to leave Berkswell on 57 for eight.
Two runs later, opening bat James Neale was lbw to Michael Hill for 15.
Tailenders Dave Brignull, eight not out, and Aditya Rai produced a few lusty blows to move the score to 73 but Rai was bowled by Hill for six and the visitors’ innings closed in the 26th over.
Berkswell made an early breakthrough in the Wombourne reply when Brignull bowled Tom Brown for two off the tenth ball of the innings.
And Brignull reduced the home side to 29 for seven in the space of ten overs, claiming all the wickets to fall.
Cheslin then picked up a wicket with his fourth ball to leave the home side on 44 for eight in the 15th over.
The ninth wicket went down in the 17th over, Ben Robinson trapped in front by Cheslin without scoring.
And Cheslin wrapped things up in his next over when Howard, six, gave an catch to Jon Coleman at cover to leave Wombourne 52 all out in the 19th over.
Brignull finished with seven for 26 off nine overs and Cheslin three for three off 2.2 overs.
Ostler said: “Having seen what was happening with the ball, we knew we had to put the ball in the right areas and let the track do the rest.”