The Bears won for the eighth time in 11 games thanks to opener Rob Yates' 66 off 51 balls and Dan Mousley's career best 4 for 28 from four overs of off-spin in Yorkshire's 176 for 8
Headingley: Birmingham Bears 180-7, Yorkshire 176-8 - Birmingham Bears won by four runs
Birmingham Bears put one foot in the quarter-finals of the Vitality Blast with a nervy four-run win over stumbling Yorkshire Vikings.
The Bears won for the eighth time in 11 games thanks to opener Rob Yates' 66 off 51 balls and Dan Mousley's career best 4 for 28 from four overs of off-spin in Yorkshire's 176 for 8.
England's Ashes hopeful Chris Woakes returned an excellent 2 for 21 from four overs.
The Vikings have now lost their past three games - six defeats in 12 - and they must now win their final two fixtures to have any chance of reaching the quarter-finals.
Birmingham should have posted more than 180 for 7,having elected to bat, but they lost regular wickets during the second half of an innings ultimately held together by left-handed Yates.
Chris Benjamin also made 45 off 27 from No.3, while Yates was run out off the last ball of the 20th over.
Dom Bess (1-16 from three overs of off-spin) and seamer Wiese (1-26 from four) stood out for Yorkshire, who were sloppy in the field - both on the ground and catching.
Yates was dropped on 50 moments after reaching his second fifty of the campaign in 38 balls.
The Bears had a bright start checked when Alex Davies on 15 steered seamer Matthew Revis's first ball to short third man - 37 for 1 in the fifth over, which became 50 for 1 after six. Yates and Benjamin settled for a couple of overs before the latter, in particular, put his foot down.
Dan Mousley of Birmingham Bears [Getty Images]
Benjamin hit five fours and a straight six in the ninth and 10th overs combined, off Revis and leg-spinner Jafer Chohan, taking the score to 92 for 1 at halfway.
However, just short of a half-century, he drilled Jordan Thompson to mid-off, leaving the Bears at 97 for 2 and staring at a bit of a collapse.
Glenn Maxwell pulled his second ball for a huge six onto the Headingley Lodge hotel's top tier. But the Australian's fireworks were only brief as he was bowled for 21 trying to get funky against Revis. And wickets continued to fall. Mousley was run out following a mixup with Yates before Ed Barnard and Jacob Bethell holed out off Dom Bess and David Wiese, leaving the score at 164 for 6 in the 18th.
Yates was strong on both sides of the wicket, pulling his only six over square leg. But the Bears weren't able to put themselves in the unassailable position they perhaps should have done.
Yorkshire also made a bright start to their innings, with Dawid Malan and Adam Lyth taking legside sixes off Henry Brookes - in for rested Hassan Ali - in the second over. But Malan holed out to deep cover off Maxwell's off-spin and James Wharton edged Woakes to slip in the next two overs - 32 for 2 after four.
Lyth looked good for 34, and so did captain Shan Masood for 21. Both played some eye-catching shots. But Yorkshire's recent Achilles heel has been batters failing to build on starts.
So when they both fell in successive overs - Lyth caught at short third man off Mousley's third ball of off-spin and Masood bowled by a beauty of a googly from left-arm wrist-spinner Jake Lintott, Vikings fans were fearing the worst at 73 for 4 in the 11th.
Mousley trapped Jonny Tattersall lbw in his next over to leave the score 87 for 5. But home hopes were raised as allrounders Thompson and Revis powerfully turned the tide. Thompson was strong to leg, while Revis hit particularly well down the ground in a brisk 54-run stand. They took the target to a still unlikely 41 from three overs at 140 for 5.
However, Woakes returned to get Revis caught at deep square leg for 32, conceding only 2 off his last over and paving the way for a comfortable run to the line for the Bears.
Mousley's third wicket was Thompson brilliantly caught at long-on by a diving Jacob Bethell for 34.
He also bowled Bess to leave Brookes with breathing space in the last, though it got closer than it should have thanks to Wiese's lusty late attack with 20.
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