Saracens moved to the top of the Aviva Premiership table with a 35-14 win in front of a sold out crowd at Allianz Park on Sunday.
A first half penalty try was followed up by scores from Joel Tomkins, Will Fraser and David Strettle after the break to secure a third successive bonus point win in the league and take Sarries four points clear at the top of the table.
Welsh got off to a poor start when a kick in the first minute was charged down by Alistair Hargreaves, leading to a penalty and three points for Charlie Hodgson.
Saracens were having the lion’s share of possession in the early stages and soon doubled their lead when Hodgson was given another kick at goal from under the posts.
Against the run of play, London Welsh scored the game’s first try after 26 minutes when Julio Cabello’s off-load bounced nicely for Seb Stegmann on the left wing to cross.
But the visitors then lost Canadian winger Phil Mackenzie to the sin-bin and a few minutes later conceded a penalty try as a Sarries lineout led to a maul that was illegally dragged down.
To make matters worse, prop Tom Bristow was yellow-carded for the offence, but while they were down to 13 men, Henson knocked over a penalty.
However, yet more ill-discipline from the Exiles allowed Hodgson to slot another penalty before Henson reduced the gap to 16-11 with a scrappy drop goal that clipped the crossbar right on half-time.
Saracens managed to put more daylight between the sides seven minutes into the second half when a sweeping move involving Hodgson and Duncan Taylor led to Joel Tomkins holding off his tackler to score, with the former converting.
Henson struck another penalty before Sarries took a huge step towards victory just after the hour mark when Strettle found Schalk Brits, whose off-load allowed Will Fraser to just finish in the corner.
The bonus point was sealed with eight minutes remaining when Saracens sealed the bonus point after Strettle went through a gap 20 metres out to score under the posts and Hodgson added to extras to seal the game.
Saracens: Wyles, Short (Ransom 69), Tomkins, Taylor (Mordt 51), Strettle, Hodgson, Wiggleworth (De Kock 51), Gill (Auterac 21), Brits (George 62), Stevens (Du Plessis 58), Borthwick, Hargreaves (Botha 56), Wray, Fraser (Saull 66), Joubert
Tries: Penalty, Tomkins, Fraser, Strette
Cons: Hodgson (3)
Pens: Hodgson (3)
Wyles, Short (Ransom 69), Tomkins, Taylor (Mordt 51), Strettle, Hodgson, Wiggleworth (De Kock 51), Gill (Auterac 21), Brits (George 62), Stevens (Du Plessis 58), Borthwick, Hargreaves (Botha 56), Wray, Fraser (Saull 66), Joubert