Neil McRoberts praised the grit and determination shown by Portsmouth in their 15-12 win at Trojans in London Three South West.
The senior coach was delighted to see his side come through their toughest test yet and remain unbeaten.
'We had to grind out a win against an experienced Trojans side,' said McRoberts.
'Trojans have the knack of dragging us into the type of game they want to play.
'It meant that we had to put in a huge shift which was something last season we wouldn't have mustered.
'Physicality was the name of the game with lots of tight carries and hard hits.
'The game was largely played within six metres either side of the breakdown.'
Trojans got on the scoreboard first after seven minutes with a good try wide out despite a brave cover tackle by Tom Hopkins.
Scrum half Tim Rollett grabbed a try to level midway through the half.
The visitors were forced to make a change when Dan Sargent went off injured to be replaced by veteran Ben Lanigan.
In the period before half-time the visitors produced some outstanding defence to ensure they went into the break on level terms.
After the restart the Portsmouth scrum began to impose their power.
After being stopped illegally three times close to the Trojans line, they were awarded a penalty try.
But with three minutes remaining Trojans notched a converted try to level once again.
With time running out, Portsmouth returned to the attack and were awarded a penalty just outside the home 22.
Hopkins kept his nerve to fire the penalty between the posts and give Portsmouth a fourth successive league win.
McRoberts had special praise for replacement Lanigan.
'Ben epitomised everything we were about,' said McRoberts.
'He rolled back the years and probably had to play for a lot longer than expected.
'All game he was one of our big ball carriers.
'Our first up defence was superb.
'To win all four of our games so far and with three of them away from home is pleasing.'
Portsmouth are second and level on points with leaders Old Tiffinians who they meet at Rugby Camp in two weeks time.