Leicester Tigers finally find their bite to keep top-four dreams alive

• Ben Youngs hails performance as best of the season• Wasps lose but see Joe Launchbury return to action• Northampton seal Premiership top spot with convincing winLeicester have endured, by their own standards, an underwhelming season but they continue to operate on a need-to-win basis. Defeat to their new neighbours would have broken their perennial presence in the top four, but it never looked likely, even when they were reduced to 14 men after 36 minutes.The Tigers, so lacking in teeth and ideas at Saracens a few weeks before, had too much wisdom for Wasps, who need to beat London Irish thi…