Find all players with the longest winning streak

I am trying to crack the problem of finding the player(s) with the longest streak of winning using Python's 3.2. I am only able to work out an unscalable solution, but I could not come up with a better one yet. Can anyone please help me with a better solution? Also, I am curious how to adapt such solution to output the player(s) with the longest winning streak per month or year?

Below is the sample dataframe players_results

Player_id     Match_Date             Match_Result
401           2021-05-04 00:00:00    W
401           2021-05-09 00:00:00    L
401           2021-05-16 00:00:00    W
401           2021-05-18 00:00:00    W
401           2021-05-22 00:00:00    L
401           2021-06-15 00:00:00    L
401           2021-06-16 00:00:00    W
401           2021-06-18 00:00:00    W
402           2021-05-14 00:00:00    L
402           2021-05-23 00:00:00    L
402           2021-05-24 00:00:00    W
402           2021-06-01 00:00:00    W
402           2021-06-02 00:00:00    W
402           2021-07-01 00:00:00    W
403           2021-05-03 00:00:00    L
403           2021-05-11 00:00:00    W
403           2021-05-12 00:00:00    W
403           2021-05-13 00:00:00    W
403           2021-05-20 00:00:00    W
403           2021-05-25 00:00:00    W
403           2021-07-06 00:00:00    L
404           2021-05-10 00:00:00    W
404           2021-05-16 00:00:00    W
404           2021-05-20 00:00:00    W
404           2021-05-22 00:00:00    W
404           2021-05-28 00:00:00    L
405           2021-05-07 00:00:00    L
405           2021-05-25 00:00:00    W
405           2021-06-06 00:00:00    L
405           2021-06-07 00:00:00    W
405           2021-06-14 00:00:00    W
405           2021-07-01 00:00:00    W

Expected Output

player_id     longest_winningstreak
403           5

My unscalable code

df = players_results.groupby('player_id').count()
df = df['match_date'].reset_index()
#record result of player_id = 401 into vector b
a = [] # record the number of consecutive "W" of player_id = 401
x = 0
for i in range(df['match_date'][0]):
    if players_results['match_result'][i] == 'W':
        x = x + 1
        if (i == df['match_date'][0]-1):
            a.append(x)
    else:
        a.append(x)
        x = 0
print(a)
b = []
b.append([df['player_id'][0],max(a)])
print(b)

c = []
y=0
for i in range(df['match_date'][0], df['match_date'][0]+df['match_date'][1]):
    if players_results['match_result'][i] == 'W':
        y = y + 1
        if (i == df['match_date'][0]+df['match_date'][1]-1):
            c.append(y)
    else:
        c.append(y)
        y = 0
#record result of player_id = 402 into the vector b
b.append([df['player_id'][1],max(c)])

d = []
z=0
for i in range(df['match_date'][0]+df['match_date'][1], df['match_date'] [0]+df['match_date'][1]+df['match_date'][2]):
    if players_results['match_result'][i] == 'W':
        z = z + 1
        if (i == df['match_date'][0]+df['match_date'][1]+df['match_date'][2]-1):
            d.append(z)
    else:
        d.append(z)
        z = 0
b.append([df['player_id'][2],max(d)])

e = []
z2=0
for i in range(df['match_date'][0]+df['match_date'][1]+df['match_date'][2], df['match_date'][0]+df['match_date'][1]+df['match_date'][2]+df['match_date'][3]):
    if players_results['match_result'][i] == 'W':
        z2 = z2 + 1
        if (i == df['match_date'][0]+df['match_date'][1]+df['match_date'][2]+df['match_date'][3]-1):
            e.append(z2)
    else:
        e.append(z2)
        z2 = 0
#print(e)
b.append([df['player_id'][3],max(e)])

f = []
z3=0
for i in range(df['match_date'][0]+df['match_date'][1]+df['match_date'][2]+df['match_date'][3], df['match_date'][0]+df['match_date'][1]+df['match_date'][2]+df['match_date'][3]+df['match_date'][4]):
    if players_results['match_result'][i] == 'W':
        z3 = z3 + 1
        if (i == df['match_date'][0]+df['match_date'][1]+df['match_date'][2]+df['match_date'][3]+df['match_date'][4]-1):
            f.append(z3)
    else:
        f.append(z3)
        z3 = 0
#print(e)
b.append([df['player_id'][4],max(f)])   

source https://stackoverflow.com/questions/70492783/find-all-players-with-the-longest-winning-streak