Reigning English Premiership champions Saracens continued their quest for a 'double Double' with a 40-19 win over London rivals Harlequins at Wembley on Saturday.
But Mako Vunipola gave the British and Irish Lions an injury scare when he limped off early in the second half with his knee heavily strapped.
The Saracens and England prop is a leading contender for one of the front-row berths in the Lions squad for the combined side's three-Test tour of New Zealand due to be announced by coach Warren Gatland on April 19.
But Saracens boss Mark McCall said he had been taken off Saturday as a precaution ahead of the European kings Champions Cup semi-final away to Irish giants Munster in Dublin in a fortnight.
"Mako took a little bang to his knee just before half-time and felt a little bit uncomfortable," McCall said.
"We don't think it's anything serious at all, but we just wanted to be sensible with the big game coming up in two weeks' time."
Saracens established an early lead over Quins thanks to tries from Chris Ashton and Schalk Brits in a match where England centre kicked 20 points.
The win, achieved in front of a crowd of 71,324, left Saracens just one point adrift of second-placed Exeter.
Meanwhile, across London, Bath coach Todd Blackadder praised his players' resolve after they came from 12 points down to beat play-off rivals Leicester 27-21 at Twickenham.
It looked as if Leicester would emerge victorious but two late tries from Bath wing Anthony Watson turned the tide. His England colleague Jonathan Joseph also crossed for a Bath try.
George Ford, the Six Nations champions' fly-half who will leave Bath for Leicester at the end of the season, converted all three tries and kicked two penalties as well in front of more than 71,000 spectators.
Victory saw Bath move level on points with fourth-placed Leicester. Only the top four sides at the end of the regular season qualify for the play-offs (two semi-finals and a final) that decide the destiny of the English title.
- 'Character test' -
"I am just so pleased that our players passed the character test in that we hadn't come back from behind before in similar situations," said Blackadder.
The former New Zealand international disagreed with those who questioned the wisdom of moving a regular season game to Twickenham by saying: "To play here was too good an opportunity to turn down -- it was a memory for all the staff, supporters and players."
Leicester assistant coach Geordan Murphy said: "We are really disappointed..."If we can go out and get our wins, then hopefully we will nick a top-four spot.
"I don't ever remember it being this tight, but it is. We have still got control of the situation."
Elsewhere Bristol interim head coach Mark Tainton vowed his side would keep going to the bitter end after an agonising 38-34 loss away to southwest rivals Exeter pushed the basement closer to relegation.
Only one team will be demoted at the end of the campaign and this loss left Bristol eight points adrift of second-bottom Worcester with just three games remaining.
Former Wales star Gavin Henson scored 19 points for Bristol, including a try, but the hosts prevailed thanks to Thomas Waldrom's try four minutes from time.
"We were minutes away from a famous victory as the players put in a hell of a shift and our defence was magnificent," said Tainton.
"It's getting more and more difficult to avoid relegation but the boys aren't going to give in and we are hoping for a big crowd at Ashton Gate next Sunday against Wasps."